Fix regression from 7ff0caaed8.

This fixes a glitch in the final boss' last form. Due to a missing
Beam::trace() call, the beam's angle was not updated,
and it always pointed into the upper left corner.
Fix possible crash due to unsafe shot iteration.

Fixes regression introduced in 0784d1b9dff.
With a std::list it was okay to create shots while iterating with an
iterator, but not so with a std::vector.
Now using index access, which is safe with push_back() operations.
Intial support for package paths (as suggested by smls).

This commit is mainly intended to ease packaging for linux.
Unless environment variable AQUARIA_DATA_PATH is set, there are two
directories which are checked by the game:
If AQUARIA_DEFAULT_DATA_DIR is defined, it will chdir there for main
operation. If it's not defined, it chdirs into the directory where
the executable is located.
Then, if AQUARIA_EXTRA_DATA_DIR is defined, it will mount this directory
and all contents into the working path, so that the files present there
will override those from the working directory when accessed by the game.

Setting the environment variable AQUARIA_DATA_PATH will disable this
behavior altogether and use *only* AQUARIA_DATA_PATH as working dir.
Use more sane defaults for CMake
More win32 cmake fixes, should now hopefully compile out of the box
Add support for "override" data directory (as suggested by smls).

Now it loads in this order:

AQUARIA_DEFAULT_DATA_DIR
AQUARIA_DEFAULT_DATA_DIR/override
AQUARIA_EXTRA_DATA_DIR
Seems this line was lost...
Remove unnecessary exception handling. Hopefully fixes build on linux.
Merge branch 'experimental'

Conflicts:
	BBGE/Shader.cpp
Fix little problem added in 54d609a8b507dd.

Respecting maxspeed lerp is not a good idea, there are nodes that set this
(normalpass, energypass, just to name two).
This causes way too fast swimming while the maxspeed lerp is > 1.
Allow overriding title screen version nuber completely.
Allow downloading data while the game is minimized.

With this change, downloads should no longer abort when the game is
minimized for more than a few seconds.
Update ttvfs to current HEAD
Fixed handling of IET_SCRIPT, rename Lua callback func getIngredientString() to getIngredientEffectString(), compile fix
Fix typos in CMakeLists.txt
Lost commit?
Fix build on OSX
Fix mantis.lua script warning, thx vegetamaker for reporting
Fix unsafe entity iteration.

It was possible to crash the game by creating many entities in a script
callback that iterates over entities, for example.
More extensions to script interface:

- obj_fadeAlphaWithLife()
- obj_setOverrideRenderPass()
- setLayerRenderPass()
- debugBreak()
- saveMenu()
- setGemPosition()
- removeGem()