Implemented invoke

See #855
Fixing includes

Signed-off-by: K-ballo <k@fusionfenix.com>
Simplified function, additionally now works with member pointers

See #855
Improved is_callable trait
Bind simplifications and refactions. Added tests from Boost

See #855
Add missing unrelated include
Revert "Bind simplifications and refactions."

Not ready yet. See #855

This reverts commit 146eb9a5c5dcad6299629867e40ff80e670517af.