Plea for updated Getting Started

[JorySchossau]

Describe the bug
The basic "hello world" example in README for 1.x or 2.xrc does not work for 1.x or 2.x

For 1.x then 2.xrc following the README, I ran into problems with setup.py, that get_nim_extensions was not defined. I found it in nexporter.py so imported it explicitly, but then ran into some variables being referenced before assignment, such as nimexe so I hard-coded the path just to progress. Then nim cache files were generated but I ran into mod_name referenced before assignment. I feel like I'm not using nimporter in the intended fashion and have bypassed a critical step. Hint, please?

[JorySchossau]

Addressed largely by PR #96.