Merge pull request #147 from mavam/unstable

Cleanup migration from cppa to caf
Remove obsolete file
Add tuple_cast to cppa headers
Add cppa/max_msg_size header
Remove unused header files
Remove duplicate code for behavior_stack_based
Remove duplicate for mailbox_based
Move all IO-related classes & funcs to caf::io
Add migration section for 0.9 => 0.10 to manual
Fix CMake options for Clang