Restored commit: Test CanGetRelativeDateString() fixed for some cases

Original commit:
Auteur:		Arkadiy Shapkin <arkadiy_s@inbox.ru>
Datum:		1 week geleden (Sun Dec 09 01:35:27 2012)
Commit hash:	0be03223a0af2c9fe77ca174d92ece0d036c21f8
Ouder{s}:	0045ffb9ce

Test CanGetRelativeDateString() fixed for some cases
GitCommandsTest project fixed
fix build warning (Warning	3 "C:\windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.CSharp.targets" cannot be imported again. It was already imported at "[...]gitextensions\GitExtensionsTest\GitCommands\GitCommandsTest.csproj (43,3)". This is most likely a build authoring error. This subsequent import will be ignored.)
Merge pull request #1 from feinstaub/topic_fixwarning

fix build warning