Add convenience function train and remove train from Net.

Conflicts:

	src/Net.cpp
Remove macros to define floating point type.
Assure randomIndices is empty in each initialization step.
This helps to reuse the current optimizer because the generateIndices
method can always create the appropriate values.
Merge pull request #39 from Ruun/indices

Assure randomIndices is empty in each initialization step.
Remove superfluous double casts.
Merge pull request #31 from AlexanderFabisch/double_precision

Remove macros to define floating point type.
Merge branch 'master' into rbm
Remove macros.
Add asserts.