Added support for SPM. Still needs work.

A problem I ran into with this easyblock is that the zip-file when extracted has a name like 'spm8', which I think is quite ugly, so I tried to flatten it (equivalent of --strip-components=1 in tar). I am not sure why deleting the original directory after moving breaks the prepare step. Would be nice if someone could comment on this.

Also I am not sure if there is a better way to check if the MATLAB module is loaded.

Stuff that needs to be done before a merge:
- Clean out the compiled MATLAB files before building (there are precompiled versions included).
- Check if the MATLAB compiler takes some kind of compiler optimization flags.
- Probably update the license.