Update:
- Googletest 1.6.0 -> Googletest 1.7.0
- Eigen 3.1.2 -> Eigen 3.2.0

Minor fix for DO.Graphics
Merge branch 'master' of https://github.com/davidok8/doplusplus
corrected FindDO.cmake.in
Recovered missing files

(Sigh....)
Fixed unit testing macro
Solved unit testing
Added zlib, libtiff, libpng, libjpeg
zlib
Cleaning code first, removing dependencies
added thirdparty libraries
corrected DO_Graphics_test.cpp
fixed warnings with clang compiler
fixed warning with clang
Minor updates
integrated zlib with some cleaning
git submodules not the way to go...
removed submodules
Squashed 'third-party/libjpeg/' content from commit bc8f8be

git-subtree-dir: third-party/libjpeg
git-subtree-split: bc8f8be222287fec977ec3f47a5cb065cceb2ee9
Merge commit '4eedbc8625d880d311446f61bc6eb24c9ecb3d7a' as 'third-party/libjpeg'
Squashed 'third-party/libpng/' content from commit c611d7e

git-subtree-dir: third-party/libpng
git-subtree-split: c611d7e912e1e3804d4a338552ca417b89daefbb