License update.

Changed from New BSD to a custom license. The new license requires a Spine license to use the code. If you have a valid Spine license, you can do whatever you like with the code. This should not be a problem for anyone using the runtimes with Spine, nothing changes. If using the runtimes without a Spine license, you now need a Spine license. This is because the runtimes were created explicitly to be used with Spine.
Merge branch 'origin/master'
Event timeline for spine-csharp.
Minor changes.
Fixed rotating UVs the wrong way.
Updated Monogame projects to include additional event timeline source files
Merge branch 'master' into monogame
Don't use properties internally.

Mono is slower using properties.
Merge pull request #116 from RandolphBurt/MonogameEventTimeLine

Updated Monogame projects to include additional event timeline source files
Merge branch 'master' into monogame