[z2292] minor CMake cleanup

- execute the CMake version check as the first thing in CMakeLists.txt
- simplify check for out of source build
- removed some unused and commented code

(based on commit [12407] - b775c74)

Signed-off-by: Xfurry <xfurry@scriptdev2.com>

(based on commit [s1935] - 50b6dc4)

Signed-off-by: Xfurry <xfurry@scriptdev2.com>