Clean up

- Rename files: gonzales.cssp & cssp.ast -> css-to-ast
- Rename files: cssp.translator -> ast-to-css
- Rename nodes: clazz -> class
- Rename nodes: funktion -> function
- Remove `fail()` function
- Remove `currentBlockLN` var -> get line number inside `throwError()` function
- Reset counters when getting tokens for a new string
- Check if token exists before doing anything else
- Divide syntax rules to separate files: rules-<syntax>.js
- Tests: require one gonzales module
- Update comments
v2.0.0-rc1