Update README.md

Added features and proposed features.
Added failing test for internal navigation properties
Fix for issue #62, support for associated internal navigation properties
Merge pull request #64 from andypelzer/issue62

Test & Fix for issue #62
Fix unit tests (issue #65)
Merge pull request #66 from andypelzer/master

Fix unit tests (issue #65)
Enabled NuGet package restore
Merge pull request #67 from andypelzer/master

Enabled NuGet package restore
Merge branch 'master' of https://github.com/refactorthis/GraphDiff into FluentAttributesRefactor