Add functions to python bindings.
Add functions to python interface.
Replace SSE by MSE.
Remove SSE from python bindings.
Gradient has been devided by number of samples already.
Simplify LMA.
Shorten debug message.
Remove unused code.
All optimizers can now be aborted with Ctrl+C.
Fix clang warnings.
Refactor mini-batch gradient.
More refactoring.
Remove duplicate code.
Remove duplicate code.
Simplify error function.
Use correct key.
Check for unrecognized stopping criteria.
Merge branch 'master' into kmeans