python: extend Net interface for outputting the overall number of parameters.
add omp parallelism to SigmaPi-Layer.
Use Optimizable::dimension() for accessing the overall number of parameters.
Merge pull request #66 from Ruun/openann

OMP parallism for SigmaPi-Layer
Only use OMP for the uncomplicated forward propagation.
(back-propagation shares error- und derivative computation
to all threads. That needs a more detailed look for optimization).

Conflicts:

	src/SigmaPi.cpp
Merge branch 'master' of github.com:OpenANN/OpenANN

Conflicts:
	src/SigmaPi.cpp
Merge branch 'master' into rbm
Use getLayer function to obtain pretrainable RBM.