Merge pull request #1818 from rogerzanoni/linuxbuild

Fix project generator build on linux
Adding of3dTriangle
changed to ofPrimitiveBase
added of3dPrimitiveBase
adding appropriate .cpp and .h files
Merge branch 'master' of https://github.com/openframeworks/openFrameworks into 3DGraphics
cleanup comments
adding 3dPrimitives Example
Removing Unnecessary images in example
Merge branch 'develop' of https://github.com/openframeworks/openFrameworks into 3DGraphics
added error checking for pulling of mesh with unsupported mode
Updated example to rebuild necessary primitives if they are not in the supported mode for pulling out their meshes
Revert "Fix project generator build on linux".

This reverts commit 8f12ae44e9973c9a1a19f5f9c2e63c0cc60b7d1f.
It was erroneously merged into master, the error was already fixed in develop.
corrected spelling of vertices and indices
moving calculating of face normals to inside of3dTriangle
as discussed in issue #1704 the ofxThreadedImageLoader was a hungry thread that did not even sleep.  This has been changed into an intelligent wait/notify thread scenario.
ofUtils: comment objective-c headers for iOS, related to #1824
Merge branch 'develop' of github.com:openframeworks/openFrameworks into develop
Merge branch 'develop' into feature-makefileRefactoring
makefiles: fix linking phase dependency with OF library