CMosek added variable bounds

Hey @iglesias I made changes in Mosek.cpp for adding bounds on variables. Unfortunately, I have to touch many files to make the arguments consistent. Could you review the little patch for me? 

I am not sure we want to add unit-test for Mosek related class. But I am pretty sure these changes make sense. I have tested them on my own computer. BTW, I think @Jiaolong will test this part of code in his GraphCut inference thoroughly. 
Yeah, I don't think it is installed on Travis at all. It would be nice to install it in the buildbot, although it might be troublesome since Mosek is not free. I'd say that for the moment is ok with checking locally every time we modify some Mosek-related code.