PLSQL built in packages

Added more complete PL/SQL built in package definitions from 12cR1 manual.

I separated each built in package to keep it organised but that results in some repetition. Combining them would result in huge regular expressions. I'm not sure which is best for performance so I went with the simplest to read and work with.

I've only added a few of the more common ones so far (the ones I've used). There are over 300 built in packages and I wasn't sure how big this syntax file or the regular expressions can get before affecting performance.

If you think it's worthwhile I can complete the whole list.