Fix a few issues in Scala lexer (#367).
Fix a few issues in Scala lexer (#367).

--HG--
branch : trunk

nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments,nex3/pygments