Many people complain that they cannot build Slicer. Mostly it's because they don't follow the build instructions. They start the build, wait for several hours, then get an error message that they cannot decipher.

It would be useful to at least make those checks that we can do:

• People still think that CMake 2.8.4 is good enough => Raise the minimum required version to 2.8.8 (at least stop with a CMake error on Windows)
• People assume that QT 4.8 must be good if 4.7.4 is required => Check the QT version and stop with an error during the configuration step if there is a mismatch

Warning is probably not enough, most people just goes on and try the build anyway and the error messages are not obvious enough.