Squashed 'CMakeModules/' changes from 1c4c56f..8865abd

8865abd Adds ASSIMP, FREEGLUT and GLEW.
9ce9913 Adds Find Avahi and DNSSD.
72b6a6d Adds Find ZeroMQ, PCAN, USB1, and GLUES scripts.
290c228 Adds FindPkg, TinyXML2 and LibFindMacros scripts.

git-subtree-dir: CMakeModules
git-subtree-split: 8865abdd0b6e7937c23b8587e44151fa845f924e
Merge commit 'de3cd2c70f46c3991772eccc662f617605671aea'
Re-add SetPlatformVars.