Implement suggestions made by boegel

* fixed file header
* drop unused import
* remove unnecessary '/' in os.path.join
* remove unnecessary blank lines
* set finalpath after moving the extracted files one level up
* do not check version of GCC and MATLAB (as this is done anyways)
* check for mcc
* fail early for mcc, GCC and MATLAB checks
* inherit from ConfigureMake instead of EasyBlock
* remove mex files that are shipped with spm (as we recompile anyways) in prepare step
* delete src directory in cleanup step
* there is a sanity check now