Fix indentation and formatting of str_clean_whitespaces
Fix some spelling in src/base/system.h

termineted -> terminated
Remove redundant MapScreenToGroup() and declarate it in RenderTools
Fix walking animation

Previously, when walking with negative x-coordinate, your walking direction was
inversed.
snd_enable_musicnow controlls menu music.

don't poll on music toggeling
Merge pull request #1206 from heinrich5991/pullreq_1206

Fix walking animation
Fixed some typos
Merge pull request #1220 from M-H-Hemeda/test-branch

Fixed some typos
Merge pull request #1148 from ghost91-/menumusic

snd_enable_musicnow controlls menu music.
Merge pull request #1204 from cinaera/clean_rendertools

Cleanup MapScreenToGroup
Merge pull request #1197 from heinrich5991/pullreq_1197

Fix some of #1138
Add enum for envelope preview modes
Add cubic bezier-FCurves support  for envelopes
Fix envelope preview commit
Correctly preview the envelope curves
Fix some numerical issues at bezier envelopes
Fix envelope editor scaling
Clamp bezier tangents and re-fix envelope preview
Remove unnecessary debug variable
Correctly name functions, remove old code and fix bezier solver