Removed the Mono classes because they will be stored in an external repository and imported as a DLL.
Squashed 'src/Assets/Accord.NET/Dependencies/Mono4Unity/' content from commit 1af8546

git-subtree-dir: src/Assets/Accord.NET/Dependencies/Mono4Unity
git-subtree-split: 1af8546f6d5e5606dcefcfd0020d1ee2772ae292
Merge commit 'a651ab43fbfddcf7bfad9774409ec6cd1cb4dca7' as 'src/Assets/Accord.NET/Dependencies/Mono4Unity'
Added the Mono classes an an external DLL.