Fix unused parameter warnings about unused parameters
Fix compiler warnings about missing virtual destructors
Fix compiler warning about useless const on returntype
Fix compiler warning about type mismatch
Fix compiler warning about inlined static function
Fix compiler warning about hidden virtual function definition
Fix compiler warning about member initializer order
Fix building with newer boost version

... using a different framework::init() API.
Fix compiler warning when building with newer boost
Give access to the number of args in InvokeArgs to support arg forwarding