ShellExtensionSettingsPage: add simple preview for context menu items
CreatePullRequestForm crash fixed. Closes #1727
Support loading dll's from Plugins folder
Lock ByNameMap to make it thread safe.
Realigned code.
Merge branch 'master' into Portable
Minor spacing issue.
Merge branch 'master' into Portable

Conflicts:
	GitCommands/Settings.cs
Merge branch 'master' into Portable
Merge remote-tracking branch 'upstream/master' into Portable
Merge remote-tracking branch 'upstream/master' into Portable
Wireup event handlers.
Merge branch 'pr/n1808_vbjay'
Suggest prune branches if remote branch no longer exist
Make selected item visible.
RunningOnXXX methods moved to EnvUtils. It will allow to register NBug before Settings class is initialized.
- Added support for wildcard branch name filters

 -  Used the git log --branches=<shell glob wildcards> option in method ProcessGitLog. If wildcards are in the filter, then the --branches option is used. Otherwise, just the branch filter without the --branches option is specified, which give the original exact match functionality.
- Code cleanup and static array extraction

- Converted tabs to spaces.
- Pulled the array of shell glob characters out to a static array.
- Show or hide tags - initial implementation

- Added menu item on View submenu to allow selecting to show or not show tabs
- Added menu handler to toggle settings and refresh view.
- Added initialization of menu item check state from settings.
- Added settings item to save user preference for showing tabs
- Removed Visual Studio's unnecessary designer file changes to isolate real work.