added a method to add a row to a problem, one method to add a column …

[giovanni-mormone]

…to a problem and a method used to nullify a row in a problem; the method used to nullify a problem simply set to 0 all variables in the given row.

I would like to have contacts with someone managing the repository, i sent an email to the coin-or contact and they said to contact you, but i have not find any contact. I made this modification because we needed it in an university project. As the coin-or person who answered me said, i also created a release of the modified version, it is compiled with the last versions of the projects used by CoinMP( e.g cbc, clp etc.) and i attached working .dll and .so to utilize this version.