Changed parser implementation to support more osascript outputs

Hi @TooTallNate, I had some issues trying to get records from osascript output (in some cases the parser returned wrong data -ie. dates-, or it hangs in a loop).

For that reason I made a new implementation of the parser using PegJS (http://pegjs.majda.cz/).

Also I added some unit tests, to document the supported cases.

The implementation is not exhaustive, some "classes" metioned here: https://developer.apple.com/library/mac/documentation/applescript/conceptual/applescriptlangguide/reference/ASLR_classes.html#//apple_ref/doc/uid/TP40000983-CH1g-BBCBJDGC are not implemented.

But they can be easily added to the pegjs grammar file.

Consider it for merge, it will resolve https://github.com/TooTallNate/node-applescript/issues/2 and other issues that I found but are not reported as bugs (like date support, or the hang when you have a complex string value - ie HTML with escape codes).

Thanks!