Sas improvements

[cedporter]

Substantial improvements to language-sas syntax highlighting.

• Added numerous language elements
• Created more granular keyword objects, for finer grained styling if desired
• Expanded keyword regex list
• Special identification of PROC SQL and the SQL that follows
• Test coverage for all added language elements

[RunDevelopment]

@cedporter
Why did you close it? There are a lot of good things in here.

[cedporter]

@RunDevelopment, just needed to clean up the commit history. It's resubmitted!

[RunDevelopment]

You can just force push in this case, although you generally don't need to clean up your commit history. We (well, git(-hub) actually) will squash all of your commits into one before committing to master.