Remove specific Lib/.gitattributes file
Add xUnit licenses

Add the license.txt alongside xUnit and also provide a copy with files
that are derrived from xUnit source code.
Add License for Moq

Provide the license for Moq alongside the binary distribution in our
Libs folder. BSD License for Moq was taken from here:
http://code.google.com/p/moq/source/browse/trunk/License.txt
Add NuGet License

NuGet is licensed under Apache 2.0 therefore we should provide a
copy of the license alongside our binary redistribution of it in
our Libs folder.  Note that because we don't ship NuGet in the
binary version of the LibGit2Sharp we don't need to inlucde
a reference to it in our NOTICE file etc.
Make Travis build fail upon a test failure
Update libgit2 binaries to 6040616

https://github.com/libgit2/libgit2/compare/16e6cee...6040616