Redefine internal keywords for syntax highlight
Redefine internal keywords for syntax highlight

* Remove hsp2 system vars, such as `prmx`, `rval`, etc.
* Remove nonstandard keywords, `true` and `false`.
* Add `thismod`.
* Lack of `ginfo_*`, `dirinfo_*`, and possibly many.
* These list should be generated by script from HDL database.

vain0/sublime-HSP,vain0/sublime-HSP