[MLP/Linear] New user-implementable activation strategy
Fixes NumPy C-API deprecation warnings (issue #126)
Closes #126
[MLP/Activation] Test fixes
Fix tests
Fix doxygen warning; Fix documentation
[MLP] First complete implementation of flexible activations and cost functions
Merge branch 'master' of github.com:idiap/bob
Fix tests
Fix copy constructor
Prepare better for Pillow support