ENH: Create CMake parser for SlicerWizard

Create a Python implementation of a CMake script parser (of sorts). This
is believed to parse most well-formed CMake script (including CMake 3.0
long brackets for strings and comments), and turns the script into a
parse tree that is well suited to editing and capable of reconstructing
the exact input document without reformatting. Use this, instead of
regular expressions, to perform the CMakeLists.txt manipulation when
adding a module to an extension.

In the long run, this will make it much easier to reliably manipulate
CMake scripts.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22956 3bd1e089-480b-0410-8dfb-8563597acbee