Updated aspectj dependency to latest stable (1.7.4).
Merge pull request #666 from aldenml/aspectj-version-upgrade

Updated aspectj dependency to latest stable (1.7.4).
Removes unused dependency management entry

Plus one indentation fix.
CreateMethodProposal refactoring

To reuse behaviour in abstract members implementation feature
Abstract members implementation added

Current version limitations:
1) There is no stub generation for abstract val/vars
2) Type parameters for defs are not generated
3) The text overlaps with the icon in quick fix menu when there is one abstract method
4) Additional brace is added to the class while invoking abstract member implementation feature from class/trait with empty body:
class Test extends TestTrait {^
}
(but for: class Test extends TestTrait {^} result is correct)
5) Stub for abstract member is not generated while invoking abstract member implementation feature if the cursor is on `class`/`trait` keyword: cla^ss Test extends TestTrait
Merge pull request #673 from skyluc/issue/unused-pom-dependency

Removes unused dependency management entry
Remove unused field.
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.
Reuses ScalaVersion from the compiler.

De-Optionalizes, De Stringifies version comparisons
Relegates Xsource setting computation to projects

THis prohibits from having a workspace-wide Xsource setting, for now.
Treats absence of XSource configuration as exception
Remove cruft, hardens version spec in prefstore
corrects the case where the user adds the XSource flag on a modern code base

Fixed error message
Cleaner error messages on version checks.
Hardens classpath test sequence
Uses the rigth preference store

Conflicts:
	org.scala-ide.sdt.core.tests/src/org/scalaide/core/classpath/ClasspathTests.scala
Merge pull request #669 from huitseeker/issue/Xsource

Xsource internal support & ScalaVersion upheaval
Removes pendingSources, which shadows sources

Fixes #1002070
Merge pull request #671 from huitseeker/pr/668

Simplifies EclipseSbtBuildManager