CreatePullRequestForm crash fixed. Closes #1727
Support loading dll's from Plugins folder
Show error callstack
Let NBug handle unexpected exceptions
Updated msysgit to 1.8.3
Changed download page to sourceforge. Added link to online manual.
Merge branch 'release/2.44'

Conflicts:
	GitUI/CommandsDialogs/FormBrowse.cs
	GitUI/CommandsDialogs/RepoHosting/CreatePullRequestForm.cs
	GitUI/UserControls/RevisionGrid.cs
Updating current file in commit window improved