This ensures that callback indices are consistent. Runtime registration as performed by NBlood has undefined order and will make savegames non-transferrable.
This removes the special handling for it in the main loop.
Some functions and variables in the kill and secret managers were also given more meaningful names.
Fixes#313
* Remove fix16.h/cpp and utilise library from m_fixed.h.
* Extend m_fixed.h with two inline functions for int to/from float operations.
* Replace fix16_floor operations with those from xs_Float.h
* Replace multiple Q16.16 conversions from 0 to just be 0.
* Replaced all found in-game bit-shifts and multiplications/divisions with inline functions from m_fixed.h
* Replaced many casts of FRACUNIT as double in SW's panel.cpp as it is converted to double by way of type promotion.
* Fixed missed precision fixes in SW's panel.cpp where some types weren't declared correctly.
* Replaced 100+ `Cos()/Sin() >> 16` operations for Blood with inline functions `CosScale16()/SinScale16()`.
- AI: there is printing error message in conosole added (instead of dassert)
- Updates for Player Control modern type
# Conflicts:
# source/blood/src/actor.cpp
# source/blood/src/actor.h
# source/blood/src/globals.cpp
# source/blood/src/globals.h
# source/blood/src/player.h
# source/blood/src/sound.cpp
# source/blood/src/triggers.cpp
# source/blood/src/triggers.h
# source/blood/src/view.cpp
# source/blood/src/weapon.cpp
# source/blood/src/weapon.h
