ValidWorkingDir renamed to IsValidGitWorkingDir

IndexWatcher exception fixed when directory is invalid
Translation: Move "Show current branch" to correct location.

(Also let VS correct the line endings.)
Merge pull request #1668 from feinstaub/topic_t1

Translation: Move "Show current branch" to correct location.
Ignore nuget packages
FormCheckoutBranch behavior fixed again when called from commit dialog

Conflicts:
	GitUI/CommandsDialogs/FormCheckoutBranch.cs
Merge remote-tracking branch 'gitextensions/master' into BackgroundFetchPlugin