Activation functions can be applied to matrices.
Use matrices instead of vectors.
Fix some bugs.
Small fix.
Merge branch 'master' into parallel-batches

Conflicts:
	src/RBM.cpp
Fix even more bugs.
Fix last bugs in test suite.
Use cwise product to compute deltas.
Correct visualization.
Correct error/gradient.
Test all error/gradient functions of Net.
Fix bugs, documentation and throw exceptions.
Refactor gradient computation.
Test cross entropy.
Add more functions to python interface.
Fix debug message.
Merge branch 'master' of github.com:OpenANN/OpenANN into parallel-batches
Fix test case.
Fix error function.

... and remove errorFromDataset.
Add ReLU test case and fix bug.