Add missing control related keywords

Add ‘While’ for WHILE loops, and REVERSE for FOR loops.
Add Integer as a Type
Add exists and joins keywords
Add keywords for drop, comment, sequences
Add exception_init and raise_application_error function
Add Pragma keyword
All variables to begin with either l or v
Allow parameters that being with p_
Remove changes to variable highlighting
Add grant keyword
Add support for additional classes

Add support for dbms_crypto, utl_raw, utl_i18n, utl_encode, owa_util,
and htp
Merge pull request #5 from jpangborn/missing-keywords

Missing keywords