Remove escaping for @external names.

fixes #106
Merge pull request #107 from dankurka/remove_external_escaping

Remove escaping for @external names.
fix issue #86 : Converter is broken with certain if conditions
Merge branch 'master' of github.com:jDramaix/gss.gwt into jd_issue_86

Conflicts:
	src/test/java/com/google/gwt/resources/converter/Css2GssTest.java
Merge pull request #109 from jDramaix/jd_issue_86

fix issue #86 : Converter is broken with certain if conditions
fix issue #103: defining @url in conditionals fails build
Merge pull request #110 from jDramaix/jd_issue_103

fix issue #103: defining @url in conditionals fails build
Enable autoconvert in GssResourceGenerator.

This is still guarded by a flag and needs to be turned on by each app.

fixes #108

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