Lp Gurobi and  Python

- Implemented a more ore less generalized lp inference solver
  which takes a lp solver as template argument ( inspired by our graphcut solver which takes a min-st-cut as template argument ) . So far Cplex and Gurobi are implemented as proof of concept.

- Added a tiny python folder to "include".
  One needs a few typedefs of the exported classes in the "include-path"
  ( a lot of python headers are changed since an include path changed )

- fixed bug in python differenceFunction - factory function

- fixed 32 bit bug in cmd interface

- Exported lp grurobi to python