Added ScalaCodeTokenizer.tokenize which takes a String instead of an IDocument.

ScalaCodeTokenizer.tokenize asked for a IDocument only to right away get the IDocument's contents and then never use it again. It makes more sense to just take the contents as a string directly, which is what this change does.
Also deprecated ScalaCodeTokenizer.tokenize(IDocument, Int, Int).
Fix potential resource leak caused by missing socket close statement
Refactorings for quickfixes

The relevance of quickfixes for the completion proposal is moved
to its own location in order to keep a better overview over them.
Merge pull request #463 from sschaef/resource-leak-fix

Fix potential resource leak caused by missing socket close statement
Improved new ScalaCodeTokenizer.tokenize API to minimise allocation of string objects on caller side.
Merge pull request #462 from jhaberstro/scala-code-tokenizer-interface

ScalaCodeTokenizer.tokenize takes String instead of IDocument.
Deprecated ScalaCodeScanner.tokenize(IDocument, Int, Int) incorrectly handled offset in generated tokens.

Also added a test.

Fixes bug introduced (into master) by SHA: e17b2ae97aaa5644d0cf1ad09ff6bc5ad039002a
Merge pull request #470 from jhaberstro/scala-code-tokenizer-fix

Deprecated ScalaCodeScanner.tokenize(IDocument, Int, Int) incorrectly handled offset in generated tokens.
Updated version of Sbt dependencies

Updated version of Sbt dependencies to 0.13.0-RC3-SNAPSHOT (when building
against Scala 2.10.3-SNAPSHOT), and 0.13.1-SNAPSHOT (when building against
Scala 2.11.0-SNAPSHOT).  The odd version number is due to the fact that we
rebuild Sbt artifacts every night against the latest Scala 2.10.3-SNAPSHOT and
2.11.0-SNAPSHOT, and hence the trailing SNAPSHOT is needed to make Maven happy.
Merge pull request #471 from dotta/transient/update-sbt-version

Updated version of Sbt dependencies
Updated .classpath for ``org.scala-ide.sbt.full.library`` project

In commit SHA: 3b7d628b8439082c9e7cc4b4400aac18e3f2f01a I forgot
to update the ``org.scala-ide.sbt.full.library`` project's .classpath.

This commit fixes the inattention.
Exposed "Restart Presentation Compiler" action

Users can now restart the presentation compiler at will.  This can be handy
when false errors are reported in a compilation unit, and you want to reset a
Presentation Compiler without performing a full clean/build.

To manually restart a Presentation Compiler, a user has to right click on the
project's folder (in the Package Explorer), and select ``Scala > Restart
Presentation Compiler``.

In order to place the functionality inside the Scala menu (as described above),
I was forced to use an `action` (and not a `command`). I did try to use a
`command`, but I couldn't find the incantantion for placing the "Restart
Presentation Compiler" inside the Scala menu when using a `menuContribution`.

Fixes #1000555
Merge pull request #468 from dotta/experimental/reset-pc

Exposed "Restart Presentation Compiler" action
Merge pull request #469 from sschaef/quickfix-refactorings

Refactorings for quickfixes