Disable useless and expensive Java goodies for Scala sources.

* quick fixes and quick assists in Scala sources have no meaning, but may trigger pauses in the UI of more than 10 seconds
* Run As/Debug As testers may trigger hierarchy calculations, inducing 10s of seconds of delay in the UI thread, for instance when scrolling through a contextual menu. This disables 'Run As Java'

Fixed #1001434. Fixed #1001178.
Merge pull request #278 from dragos/issue/disable-quick-java-assists-1001434

Disable useless and expensive Java goodies for Scala sources.
Correct partitioning of octal sequences in character literals

The previous behavior was not correct because an octal sequence can
start not only with a '0' but with all signs between '0' and '7'.

Fix #1001443
Add syntax highlighting for escape sequences in character literals

Fix #1001444
Refactoring in ScalaSourceViewerConfiguration

- Grouping of code highlighting parts
- Allow iteration of components instead of managing them
  manually to reduce errors
Merge pull request #275 from sschaef/issue/partitioner-correction

Correct partitioning of octal sequences in character literals
Merge pull request #276 from sschaef/issue/escape-sequences-characters

Add syntax highlighting for escape sequences in character literals
Merge pull request #277 from sschaef/issue/sourceviewer-refactoring

Refactoring in ScalaSourceViewerConfiguration