Fix for Facet editor

The ProjectSdksModel is now chosen using a null-project which is
apparently sufficient.  ALso if the selected SDK is null, the
DefracFacetEditorTab won't run into an NPE.
Fix for Macro and Delegate annotations

- Unspecific annotation in specific module is no longer requiring
  invalid implementations
- Delegate constructors checked correct
- Don't skip Javac as long as IntelliJ doesn't want to build project
Fix for Macro and Delegate annotations

- Don't let the CreateClassOrPackageFix throw an exception
- Don't search for usage of type parameters
- Don't generate useless fix for missing delegate ctor
- Don't check type parameters for method signatures
Land @Unsupported

Currently not fully supported in the plug-in but reference expressions
are already checked. Method declarations and fields must be checked
for their signature.
Enable @Unsupported annotator

Annotator is enabled in the plug-in and annotates usages of unsupported
code in references as well as declarations. Partially unsupported
methods in generic code are annotated using a warning.
Fix for validation of @Macro

Ann error was reported for a macro bound to an overloaded method. In
that case all alternatives have been validated, which is incorrect.
The validation will happen only for the single method with matching
arity. If no such method is found, a quick fix to create a new method
 is shown. If one method with broken signature is found, a fix to
 change its signature is shown as well since we believe this is the
 common case.
Fix for validation of @Delegate

Compiles with JDK6 now so that IntelliJ which is running by default
on JDK6 is no longer complaining about mismatched class version.

All *Util* methods are now statically imported to reduce clutter in
method bodies.
Don't omit skip-javac check
DefracPsiUtil#compareBytecodeTypes: Check for component type of Array
Augment default.settings with references

The MainClassReferencesSearch is currently not working and therefore
not enabled in the plugins.xml -- code is committed so we can ask for
guidance at the IntelliJ forums.
Merge pull request #14 from joa/master

Fix facet editor and annotators. Introduce file type for default.settings