#1247: Permanent CommandBar installation

Conflicts:
	GitPlugin/Connect.cs
	GitPlugin/Plugin.cs
Add full relative path to doubleclick of item in file tree.

Double clicking a submodule would fail because `item.Name` is not a relative path.  Please check that there are no other downstream effects by this change.
Fix slow settings load because of UNC paths.

Make the default clone combobox a lazy loaded list (loads when first dropped).
Edit GetParentPath to ignore UNC paths.
Added option to set base url so it will work with SSH urls now.

Stricter matching to prevent false positives.
Added "View pull requests" tab in windows form.
Added approve and merge pull request classes.

Added GetPullRequest class
Add merge and approve function
Add approve and merge buttons to form
Performance optimizations

Added threading to prevent gitextensions from not responding while loading pull requests
Bug fixes
UI changes
UI Changes
Cleaning, refactoring and little more fault tolerant
Merge branch 'pr/n2139_TheGeoist'
Merge branch 'pr/n2157_NamesTwister'
Merge branch 'pr/n2140_vbjay'
Merge pull request #2110 from gitextensions/permanentcommandbar

VS Plugin make CommandBar permanent (position handling of CommandBar)
Updated msysgit to 1.8.4
Increased performance and lowered memory footprint of DvcsGraph

- Do not calculate entire graph, only calculate visible part
- Faster implementation of GetRevisionsChildren
- Less locking
Updated Dutch translation