Reviewed by Tony Chang.

        "WebCore/css/makeprop.pl" and "WebCore/css/makevalues.pl" should take ENABLE_ flags into account
        https://bugs.webkit.org/show_bug.cgi?id=62114

        Changed the line commenting style in WebCore/css/*.in files from "#" prefixed to "//" prefixed.
        That's needed because we now pre-process the files with the C++ pre-processor. Also, there's
        no need to manually strip the comments anymore.

        Moved the duplication checks from project files to makeprop.pl and makevalues.pl.
        In addition makevalues.pl will also lower case the values.

        This is a build script refactoring, so no tests are provided.

        * CMakeLists.txt:
        * CodeGenerators.pri:
        * DerivedSources.make:
        * GNUmakefile.am:
        * WebCore.gyp/WebCore.gyp:
        * WebCore.gyp/scripts/action_csspropertynames.py:
        * WebCore.gyp/scripts/action_cssvaluekeywords.py:
        * css/CSSPropertyNames.in: comment style only
        * css/CSSValueKeywords.in: comment style only
        * css/SVGCSSPropertyNames.in: comment style only
        * css/SVGCSSValueKeywords.in: comment style only
        * css/WCSSValueKeywords.in: comment style only
        * css/makeprop.pl:
        * css/makevalues.pl:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@89362 268f45cc-cd09-0410-ab3c-d52691b4dbfc