Add highlighting preference for Dynamic calls

The default colors for the new preferences are taken from already
existing highlighting classes. selectDynamic and updateDynamic are
highlighted as template vars, whereas applyDynamic and applyDynamicNamed
are highlighted as methods.

A new Dynamic category is introduced to the syntax coloring preference
page.
Remove needless information from preference page

It is already clear that the Scala preference page highlights Scala
symbols, no need to add this information again in the displayed name
of the ScalaSyntaxClass.
Reinstate Scala templates (broken when restructuring packages).
Correctly determine if compiler settings were changed through the UI.

Also, make sure the dialog prompt to clean all projects appears only when settings were really changed.

Fix #1002075
Remove all traces of `Trim`

This class never really pulled its wait. Since it was the root cause of
the bug just fixed, the only remaining use was removed. It conflated `String.trim` and `isEmpty`
in one go.
Merge pull request #665 from dragos/issue/rebuild-too-often

Don't clean workspace unless compiler settings really changed
Merge pull request #655 from sschaef/t-syntax-coloring-pref-for-dynamic

syntax coloring pref for dynamic
Merge pull request #660 from huitseeker/issue/Preferences

Replaces PropertyStore with a set of sparser platform calls.
Indent templates to the same indentation as the line of the insertion point.

Simple solution that makes templates usable: even if they are not properly indented,
multi-line templates now align to the first non-whitespace character of the insertion point.

No tests because this is purely UI code.

Fix #1000058, #1000626,
Merge pull request #663 from dragos/issue/template-engine

Re-enable and improve Scala Templates
Refactor scala version comparisons, better handling of unkown versions
Extends compatible versioning to cover for the XSource case.

Changes Error to suggest use of the XSource flag.