Delete HavokMagicSpells.h
Rename folders according to new convention
Docs: Add hrengin conventions document
Docs: Move obsolete documens to `obsolete` folder
Graphics: Remove duplicates

Some time ago those were intended to be rewritten into OSG wrapper, and
since then forgotten.
Physcis: Rename hrenginphysics to physics-bt
Audio: Create OpenAL Soft wrapper

This is only a basic wrapper, but it provides almost the same
functionality as the previous BASS wrapper.

- threaded sound play
	still needs some work, currently consumes excessive cpu power
- WAVE RIFF loader
	no other formats
- sounds are still hardcoded
Docs: Update HDF format description
HDF: Add few example documents

Copied documents describing actual ingame physics models.
Docs: Update HDF description
Audio: Remove hardcoded sounds

Loading sounds is now a job for game itself, not the hrengin.
Audio: Implement ISound class

I cleaned up audio code, now sound has it's own class, buffers are now
stored it CSoundManager::SoundMap_, so they aren't recreated each time.
As always, error handling is not present yet.

Also I renamed ::hrengin::sound namespace to ::hrengin::audio, to match
the module name.
Audio: Add todolist

Added todolist file, and some future stuff.
Audio: Remove graphics dependency

...and fix some newlines
Update hrengin_conventions.md
Update README.md

Now this readme describes the branch, not project.
Update README.md
Docs: Update HDF documentation

Minor update, updated version up to 1.1.3
Audio: Add wave formats

Borrowed that enum from SO
Merge branch 'core-rewrite' of https://github.com/Huddayn/hengine into core-rewrite