ref #23 : integrated culling into gui, fixed bug concerning bounding boxes containing the whole view frustum, changed vec4s into vec3s in view frustum data structures because the dot product does not use the semantics of homogenous coordinates
ref #23 : delete resolved TODO comment
Ref #23: Fix frustum return values
Merge branch 'master' into culling2_23

Conflicts:
	libs/core/abstractscenepainter.h
	libs/gui/viewer.cpp
	source/cgsee/painter.cpp
	source/cgsee/painter.h
	source/gui/include/gui/viewer.h
	source/gui/source/viewer.ui
Remove redundant files (leftover from merge)
add conditions for mac os
Update swizzle macros, ref #128
Merge pull request #145 from hpicgs/apple_support/preproc

add conditions for mac os
Merge pull request #114 from hpicgs/culling2_23

ref #23 : integrated and improved view frustum culling
merge master into navigation develop branch, ref #153