Add cinoptions to Vim modelines

The cinoptions option helps Vim auto-indent code more correctly, if not
perfectly.
Fix indentation
Merge pull request #3 from magicant/fix/modeline

Add cinoptions to Vim modelines and fix indentation
Add SourceLineLocation class
Move SourceLocation to sesh::parser
Change SourceLocation count base to 0
fixup! Add SourceLineLocation class
Redefine SourceLocation using SourceLineLocation
Add SourceLocation comparison operators