[CMake] Add WTF_USE_*_UNICODE variables
https://bugs.webkit.org/show_bug.cgi?id=114556

Reviewed by Brent Fulgham.

WTF_USE_ICU_UNICODE and WTF_USE_WCHAR_UNICODE are used to
reduce duplication in the platform specific CMake files.

.:

* Source/cmake/OptionsBlackBerry.cmake:
* Source/cmake/OptionsEfl.cmake:
* Source/cmake/OptionsWinCE.cmake:

Source/JavaScriptCore:

* CMakeLists.txt:
* PlatformEfl.cmake:

Source/WebCore:

* CMakeLists.txt:
* PlatformBlackBerry.cmake:
* PlatformEfl.cmake:
* PlatformWinCE.cmake:

Source/WTF:

* wtf/CMakeLists.txt:
* wtf/PlatformBlackBerry.cmake:
* wtf/PlatformEfl.cmake:
* wtf/PlatformWinCE.cmake:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148463 268f45cc-cd09-0410-ab3c-d52691b4dbfc