core libs inconsistencies

In writing Apothecary, I noticed a number of small inconsistencies in the libs folders. I'm noting them here.

Assimp

Why is assimp needed for osx in the core libs? I'd think we'd want it in ofxAssimpModelLoader/libs.

Freetype weird nested folder structure

The include path is freetype/include/freetype2/freetype instead of freetype/include.

I assume this is due to weird include paths in freetype?

FreeImage naming

Shouldn't "FreeImage" be "freeimage" to match the lower case lib name convention in OF?

tess2

I'd think the tess2/Sources folder should be tess2/src

Also, the compiled library has the "lib" prefix while all other libraries are renamed without it:

libtess2.a -> tess2.a

rtAudio naming

Shouldn't "rtAudio" be "rtaudio" to match OF lower cased lib name conventions?

Cairo

The win_cb libraries all have the "lib" prefix, while the other cairo platform builds do not.

Start by inspecting the core libs folders and comparing the Assimp, Freetype, FreeImage, tess2, rtAudio, and Cairo layouts and library names across platforms. Determine the intended conventions for locations, casing, include paths, and prefixes; done means the listed inconsistencies are resolved consistently or their exceptions are documented.