ShellExtensionSettingsPage: add simple preview for context menu items
Submodule GitExtensionsDoc updated.

Submodule GitExtensionsDoc:
    < 439e4cb - add section about re-taggin
Partially revert "ConfigFile.GetConfigSections() transformed to property"
DateTime format moved to function GitCommandHelpers.GetFullDateString(). Refs #1782
Removed dot from message generated for submodules
remove nuget restore packages for non windows for now
Merge pull request #1786 from fraga/fixMoreMonoBuild

remove nuget restore packages for non windows for now
Separate methods for nullable enums.
ConfigFileParser - handles comments, escaped values, quoted values.

TODO: recreate comments when saving config file.
Fixed constructor for translation.
Progress bar added to FormTranslate that display loading progress
Changed settings to use file and added IsPortable application setting.
Consolidate switch statements.
Ignore NUnit GitExtensions.*.sln.VisualState.xml
Don't use timer functionality and save file explicitly.
Fix logic for when to decode or just try to return the value.
Add NoMono parameter to nuget script.

Allows script to be run on a machine that has .net and not Mono and can't install the package manager.
Revert "Fix logic for when to decode or just try to return the value."

This reverts commit caabe83197cd05f87263f5cb400d3fedf910ebf2.
Fix logic for when to decode or just try to return the value.
Add import from registry functionality to read the settings from the registry and store them in the settings file.