fix issue #90 and #91
Merge pull request #96 from jDramaix/jd_fix_91

fix issue #90 and #91
fix issue #90
fix issue #85
Merge pull request #99 from jDramaix/jd_fix_85

fix issue #85
Merge pull request #98 from jDramaix/jd_fix_91

fix issue #90
Add failing test for missing commas in @external statement.

gwt-dnd was missing a comma in an @external statement and was
not failing the build due to that.

fixes #78

Move @external rules to top level since GSS expects them there.

fixes #89

Conflicts:
	src/main/java/com/google/gwt/resources/converter/Css2Gss.java
	src/main/java/com/google/gwt/resources/converter/GssGenerationVisitor.java
	src/test/java/com/google/gwt/resources/converter/Css2GssTest.java