SimpleMap improvements.
SimpleMap improvements.

- Changed SimpleMap to hold two maps for keys and values respectively, instead of needing to convert properties back to keys.
- Implemented SimpleMap.delete() and SimpleMap.clear()

Arnavion/libjass,Dador/libjass,joshuabrown-ellation/libjass,joshuabrown-ellation/libjass,Arnavion/libjass,Dador/libjass,joshuabrown-ellation/libjass,Dador/libjass,Arnavion/libjass