Added support for github releases and OS windows for travis

[rdoering]

I added release-deployment for git-hub which is working as a charm as shown here. You only have to

1. create new access-token with permissions "read:org, repo, user:email" for travis
2. put this access-token as ENV-variable into your travis-setting of this repo called "GITHUB_API_KEY"

The 2nd point is the new support of MS-windows by travis, which is using "make build", too. This is failing but is failing while compiling libgit2.