Some code refactoring

Changed vehicule (french) to vehicle (english) in enums and variables
Merge branch 'dev' of github:colobot/colobot into dev
Fix for shadows (bugs #176 and #132)
Merge branch 'shadow-bug' into fix-for-shadows
Merge branch 'fix-for-shadows' of https://github.com/xiendev/colobot into xiendev-fix-for-shadows
Fixed problem with test compilation

Altered test cmake files to fix linker problem.
Changed tga to png in pyro.
Changed enum in CMotionDummy.
Added new Intro music (by PiXeL)