CMake support

[mscuttari]

I added the necessary files to make the project compatible with CMake and thus with IDEs such as CLion by JetBrains. The main reason I did this is because I was having a lot of troubles with Netbeans not recognizing the included headers and subsequently with the autocomplete feature. When using for example CLion, the IDE will show two build targets: one is for the whole project and the other is for the kernel. I was not able to hide the last one, but anyway it is automatically built while building the first target, so it's just a menu entry that doesn't hurt anything. The only thing I did not manage to do is the usage of perl script invoked during the kernel build.