Fix for "fatal: Not a valid object name" when displaying a nonexistent file blob

When browsing through file history: a click on a commit containing deletion of the file caused the error.
Merge pull request #2501 from qgppl/gp/fix-FileViewer

Fix for "fatal: Not a valid object name" when displaying a nonexistent blob
.nuget directory case fixed
Settings stored at the Distributed level always have to be set directly
Merge branch 'release/2.48'
Tests for PathUtil added
.nuget directory case fixed
Installing GitCredentialsHelper fixed. Closes #2467, #2483
Should fix command bar position saving in some cases. Closes #1493

Previous code works for me for all VS except 2010, new one should fix this for VS2010. If it doesn't help for you, try reset addin.
Version updated to 2.48.02
Backslash correction turned off for URLs. Closes #2509
Double appearance of "Current unstaged changes" fixed. Closes #2407
Uninstall action added to uninstaller. Closes #1079
Change log updated
Merge branch 'release/2.48'

Conflicts:
	GitUI/Resources/ChangeLog.md
Update the Nuget executable when running the script.
Updated Nuget to version 2.8.2
Update nuget when building the installer