Reorg

This is a reorg of sources. Basically the library OpenMEEG is moved to libs and includes are separated from C++ files. Some other minor changes is a removal of a non ascii character in a docstring which prevented python bindings to work (why it did no appear before is a nystery) and the removal of some directories from the doxygen processing. MatLib directory is also renamed to OpenMEEGMaths to be coherent with the library name. Oh and I switched to #pragma once almost everywhere.

Next will be the superproject...