Fix matlab non-member functions inline doc issue (visible doxygen syntax).

- Fix gen_doc/gen_matlab_inline_doc_from_doxy_blocks.sh in order to manage files with only a function (instead of class).
- Add the script gen_doc/filterout_matlab_doxy_blocks.sh to avoid the doxygen block to take over the matla inline doc in matlab... (a problem that doesn't not occur for class functions, it happens only to non-member functions).
- Other minor fixes.