COMP: Set "Slicer_LANGUAGES" global property only if i18n support is enabled

Prevent confusion and make global property definition consistent.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21890 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: Fix import of Tkinter and Fix compilation errors on VS 2010 and 2012

Updated CMake'ified python external project to include the following
topics:
* 60ee828 - Merge branch 'add-lib-tk-to-pythonpath'
* 8a3c51a - Merge branch '8-add-ctestconfig'
* 22a0870 - Merge branch 'fix-msvc2012-build-error'
* a70729f - Merge branch 'fix-msvc2012-link-error'

See https://github.com/davidsansome/python-cmake-buildsystem/pull/13
Fixes python-cmake-buildsystem issue 13

See http://www.na-mic.org/Bug/view.php?id=3065
Fixes #3065

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21891 3bd1e089-480b-0410-8dfb-8563597acbee