Make destructor virtual to fix a g++ warning (-Wnon-virtual-dtor)
Fix g++ warning: 'DeepBeliefNet::myRBMs' should be initialized in the member initialization list [-Weffc++]
fix g++ warning: declaration of 'energy' shadows a member of 'this' [-Wshadow]
Fix Weffc++ warning on other constructors too...
Fix g++ warning: 'Random::rng*' should be initialized in the member initialization list [-Weffc++]
Non need for a separate constructor here
Fix g++ warning: switch missing default case [-Wswitch-default]
Make these conversions explicit
Fix clang warning: no previous prototype for function [-Wmissing-prototypes]. Cleanup.
fix clang warning: extra ';' after member function definition [-Wextra-semi]
Fix clang warning: will never be executed [-Wunreachable-code]
Fix clang warning: no newline at end of file [-Wnewline-eof]