Fix build error simplifying CMakeLists.txt

Before this commit, VTK and ITK libraries were passed as
INCLUDE_DIRECTORIES. This was causing the following error:

cc1plus: error: /home/kitware/Dashboards/Nightly/Slicer-build-64bits-QT4.8.5-PythonQt-With-Tcl-CLI-Release-nightly/zlib-install/lib/libzlib.a: not a directory
Minimize confusion removing unused file "cmakeConfig.h.in"
Merge pull request #1 from jcfr/fix-build-error-and-other-tweaks

Fix build error and other tweaks