C++11 patchset 9: move hardcoded init parameters to class definitions (part 1) (...

C++11 patchset 9: move hardcoded init parameters to class definitions (part 1) (#5984)

* C++11 patchset 9: move hardcoded init parameters to class definitions

C++11 introduced the possibility to define the default values directly in class definitions, do it on current code

Also remove some unused attributes

* CollisionInfo::bouncy
* collisionMoveResult::collides_xy
* collisionMoveResult::standing_on_unloaded
* Clouds::speed

* More constructor cleanups + some variables removal

* remove only write guiFormSpecMenu::m_old_tooltip
* move header included inside defintions in genericobject.h
* remove some unused since years exception classes
* remove unused & empty debug_stacks_init
* remove unused & empty content_nodemeta_serialize_legacy
* remove forgotten useless bool (bouncy) in collision.cpp code