setup particle calculation on the gpu

Works so far, but on my (nvidia 650ti) it's slower than on the cpu..
add horizontal bluring
merge master into branch
add depth blurring step, generalize post processes inside the water particle rendering #30
Merge remote-tracking branch 'origin/master' into GpuParticles
GPU/CPU switch with "G" key press

fix cuda shutdown
add bluring with a bug #30
add diffuse light + simple specular light #30
merged master #30
remove doubled function string push to lua stack. #76
add error check before lua_close() in destructor. #76
rename m_lua to m_state in LuaWrapper to match functionality better. #76
rename pushArgument to push because it just means to push a value onto the lua stack. #76
Merge branch 'master' into water_rendering_30
complete rework of function-calling. #76

* no more need to call callFunc() and fetchResults() seperately.
* function calling and return values receiving now with LuaWrapper::call<RetTypes...>(funcName, Args...)
* single return value just stored in variable reference, multiple return values stored in std::tuple unpacked with std::tie
add binoial coeff calculation #30
Merge branch 'water_rendering_30' of http://github.com/lanice/elemate into water_rendering_30
hide lua.hpp from public again by removing it from luawrapper.h. #76
linearize water depth values, use scene+hand depth in flush shader #30
clean up and add const correctness. #76