updates to calibration assistant function

- low both long and short-term stability are considered in an effort to detect when there is outliers/noise in the last 90 minutes (configurable) or situations that indicate that either carbs or insulin would have been used recently that could mean the BG is about the change
- variable/constants renamed for clarity
- alert logic changed. If the user is informed that their BG has been rising/falling, there is no need to inform that that their BG is also unstable
- in the long term instability message, the number of minutes are added so that the user understands that it's a historical issue, not just with current BG values.

xdrip/Constants/ConstantsCalibrationAssistant.swift

@@ -11,23 +11,31 @@ import Foundation
 /// constants used by the calibration assistant
 enum ConstantsCalibrationAssistant {
 
-    /// the number of minutes of readings that we should use for the calibration assistant calculations
-    static let minutesToUseForCalculations: Double = 20
+    /// the number of minutes of readings that we should use for the long-term calibration assistant calculations
+    static let minutesToUseForLongTermCalculations: Double = 90
+
+    /// the number of minutes of readings that we should use for the short-term calibration assistant calculations
+    static let minutesToUseForShortTermCalculations: Double = 25
 
     // Delta
     /// the value over which we will consider that the delta change is significant to display as a concern to the user
-    static let deltaResultLimit: Double = 90
+    static let shortTermDeltaResultLimit: Double = 90
 
     /// the weighting that will be applied to the delta change value to push the result up
-    static let deltaMultiplier: Double = 30
+    static let shortTermDeltaMultiplier: Double = 30
+
+
+    // Standard Deviation (long-term)
+    /// the value over which we will consider that the long-term variance value is significant to display as a concern to the user
+    static let longTermStdDeviationValueLimit: Double = 20
 
 
-    // Standard Deviation
-    /// the value over which we will consider that the variation in change is significant to display as a concern to the user
-    static let stdDeviationResultLimit: Double = 60
+    // Standard Deviation (short-term)
+    /// the value over which we will consider that the short-term variance result is significant to display as a concern to the user
+    static let shortTermStdDeviationResultLimit: Double = 60
 
-    /// the weighting that will be applied to the standard deviation value to push the result up
-    static let stdDeviationMultiplier: Double = 50
+    /// the weighting that will be applied to the short-term standard deviation value to push the result up
+    static let shortTermStdDeviationMultiplier: Double = 50
 
 
     // Very high BG levels

xdrip/Storyboards/en.lproj/CalibrationRequest.strings

@@ -11,7 +11,8 @@
 "doNotCalibrate" = "You should not calibrate now. Wait for a better time";
 "bgValuesRising" = "BG values have been rising";
 "bgValuesDropping" = "BG values have been dropping";
-"bgValuesNotStable" = "BG values are not stable enough";
+"bgValuesNotStableShortTerm" = "BG is not currently stable";
+"bgValuesNotStableLongTerm" = "BG values have been unstable over the last %@ minutes";
 "bgValueTooHigh" = "Current BG value is too high";
 "bgValuesSlightlyHigh" = "Current BG value is slightly high";
 "bgValueTooLow" = "Current BG value is too low";

xdrip/Storyboards/es.lproj/CalibrationRequest.strings

@@ -11,8 +11,9 @@
 "doNotCalibrate" = "No se debe calibrar ahora mismo";
 "bgValuesRising" = "Los valores de glucosa han estado subiendo";
 "bgValuesDropping" = "Los valores de glucosa han estado bajando";
-"bgValuesNotStable" = "Los valores de glucosa son poco estables";
-"bgValueTooHigh" = "La glucosa actual es demasiado alto";
-"bgValuesSlightlyHigh" = "La glucosa actual es ligeramente alto";
-"bgValueTooLow" = "La glucosa actual es demasiado bajo";
-"bgValuesSlightlyLow" = "La glucosa actual es ligeramente bajo";
+"bgValuesNotStableShortTerm" = "Los valores de glucosa son poco estables";
+"bgValuesNotStableLongTerm" = "Los valores de glucosa no han sido suficientes estables durante los últimos %@ minutos";
+"bgValueTooHigh" = "El valor de glucosa actual es demasiado alto";
+"bgValuesSlightlyHigh" = "El valor de glucosa actual es ligeramente alto";
+"bgValueTooLow" = "El valor de glucosa actual es demasiado bajo";
+"bgValuesSlightlyLow" = "El valor de glucosa actual es ligeramente bajo";

xdrip/Texts/TextsCalibration.swift

@@ -44,8 +44,12 @@ enum Texts_Calibrations {
         return NSLocalizedString("bgValuesDropping", tableName: filename, bundle: Bundle.main, value: "BG values have been dropping", comment: "a message to inform that the BG values have been dropping too much to calibrate")
     }()
 
-    static let bgValuesNotStable:String = {
-        return NSLocalizedString("bgValuesNotStable", tableName: filename, bundle: Bundle.main, value: "BG values are not stable enough", comment: "a message to inform that the BG values are not stable enough to calibrate")
+    static let bgValuesNotStableShortTerm:String = {
+        return NSLocalizedString("bgValuesNotStableShortTerm", tableName: filename, bundle: Bundle.main, value: "BG is not currently stable", comment: "a message to inform that the BG values are not stable enough to calibrate")
+    }()
+
+    static let bgValuesNotStableLongTerm:String = {
+        return String(format: NSLocalizedString("bgValuesNotStableLongTerm", tableName: filename, bundle: Bundle.main, value: "BG values have been unstable over the last %@ minutes", comment: "a message to inform that the historical BG values are not stable enough to consider calibrating"), Int(ConstantsCalibrationAssistant.minutesToUseForLongTermCalculations).description)
     }()
 
     static let bgValueTooHigh:String = {