Improve Scala highlighting.

This commit adds support for highlighting Scala types and type
parameters, and fixes support for method and class names.
Attribution of Nate Cook (@natecook1000) and Matt Diephouse (@mdiep) in AUTHORS* and language files.
Tidying up CHANGES in preparation to 8.1.
Version 8.1
Fixed broken handling of <br>:

- Dropped non-pre container test as it relied on the old local
  useBR param which is now replaced with a global option, so
  there's no easy way to test it on the same page.
- <br> is now replaced with \n unconditionally.
- Literal \n removed on useBR: true.
- Normalized HTML is assigned to a node to get its textContent.
- Merging is attempted only on the original stream is called only
  if there's `<` in the text.
Faster useBR.

Dropped usecase of using <pre> with <br> as unconditional replace
of <br> requires constructing another node and parsing HTML which
is too expensive.
Merge remote-tracking branch 'upstream/master' into topic/scala-improvements
Address initial review comments from @isagalaev.
fix missing if
Merge pull request #504 from ingwinlu/fix_erlang_if

fix missing if
Fixed syntax
Merge pull request #505 from hatch2/features/fix_kimbie_dark_syntax

Fixed syntax
Fix incorrect indention of iOS devices
Merge branch 'bug/ios-indention'

closes #409
Colors in compliance with WCAG 2.0 AA

Darkened one of the colors to be compliant with WCAG  2.0 AA requirement contrast ratio (4.5).
Merge pull request #510 from Nettsentrisk/patch-1

Colors in compliance with WCAG 2.0 AA
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.