dCGPANN and general performance improvements

New Features

• dCGP-ANNs are added to the available expressions
• New kernels are available for CGP
• CGP expressions can be evaluated in parallel
• backpropagation is implemented in dCGPANNs

Bug Fixes

• Protected division had several issues and is now working as expected
• The dCGP headers have an improved usability in third party projects