Add linux/gcc cmake, fix some compilation/physx issues
fix fmod cmake for linux
Fix some more issues, physx linking not working
fix linkage on windows
using physx33 #66, seems to fix linking on linux
clean up to px3.3, set some compiler flags
fix some warnings with gcc
fix terrain creation on linux

use std:: prefix for abs, pow
ensure that drawing of (transparent) water after base terrain

use map and std::less implementation for TileID instead of unordered_map.
So transparent layers have to have the highest levels.
Discard water fragments below the corresponding base terrain tile
fix link+build+warnings with VisualStudio, again. #66
add ifndef LINUX define to main.cpp to prevent crashing unter bumblebee/optirun
change ifndef to BUMBLEBEE which has to be manually set now in cmake command to disable the commands that cause the program to crash under optirun.
Merge branch 'TargetLinux' into fix_navigation_67
remove m_rotation from initializer list in Navigation. #67
make move() rotate() and pitch() protected in Navigation. 67
fix #56. #67