Improve Scala highlighting.

This commit adds support for highlighting Scala types and type
parameters, and fixes support for method and class names.
Merge remote-tracking branch 'upstream/master' into topic/scala-improvements
Address initial review comments from @isagalaev.
Restructuring scala.js based around @isagalaev's comments.

This commit removes a lot of the complex structure, specifically around
parameter lists and class definitions -- which were not totally correct
and introcued other problems.

It also adds support for unicode method/type names when necessary, and
correctly tags type names and type arguments with the 'type' className.
Generlize style support for .hljs-type and .hljs-typename.

Previously most type and typename styles were language-specific.
Under isagalaev's direction I have generalized these, and done
some work to unify type and typename.
handle val like def
Update Scala example code.

This commit changes the example to use a wider variety of Scala
syntax. It also fixes a small bug with semicolons.
add a few more examples
Merge branch 'topic/scala-improvements' of github.com:non/highlight.js into scala
Zeroed relevance of Scala types.
Removed leading line-break from Scala snippet.
Adding Erik Osheim (@non) to AUTHORS.
Noting Scala rework in CHANGES.