Allow footstep sounds to play for liquid and ladder nodes, making swimming and climbing sounds possible

Signed-off-by: Craig Robbins <kde.psych@gmail.com>

NOTE 1: This does not mean a 2x increase in framerate. Increase in fps may be up to 1-2fps
NOTE 2: This local 'caching' of settings is not optimal and an alternative solution will be worked on after 0.4.11 is released

Signed-off-by: Craig Robbins <kde.psych@gmail.com>

- Don't create and cache an extruded mesh for every (non-node) item.
  Instead use a single one per image resolution.

- For cubic nodes reuse a single wield mesh too

- Improve lighting of the wielded item

- Increase far value of wield mesh scene camera, fixes #1770

- Also includes some minor refactorings of Camera and GenericCAO.

Add (experimental) support for topbottom as well as sidebyside 3d mode

Add support for (configurable) multiline hotbar
Improved screensize handling
Add userdefined gui scale by BlockMen

Swing the camera down when the player lands on the ground, based on the velocity the surface is hit with.

Switch the license to be LGPLv2/later, with small parts still remaining as GPLv2/later, by agreement of major contributors