refactor compile time operators and ForEach

- types.h: add namespace bmpl as global default for boost::mpl
- Identity.hpp: Identity<> inherit from boost::mpl::identity
- include/compiletime/*: use new lambda notation to define operators
- fix all pmacc and picongpu parts which use compile time operators
- rewrite ForEach (less BOOST PP code generation, use boost lambda functors)

Some of the changes are needed for the multi particle branch.