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

pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments,pathawks/pygments