Submodule GitExtensionsDoc updated

Submodule GitExtensionsDoc:
    > a120c4e - Fix incomplete sentence.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of git://github.com/gitextensions/gitextensions
Merge branch 'master' of git://github.com/gitextensions/gitextensions
Merge branch 'master' of git://github.com/gitextensions/gitextensions
Merge branch 'master' of git://github.com/gitextensions/gitextensions
Merge branch 'master' of https://github.com/gitextensions/gitextensions
Merge branch 'master' of git://github.com/vbjay/gitextensions
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Add submodule fetch option to BackgroundFetch plugin
Add Fetch All Submodules sample script
Support VS2013 build
Include Git.hub.dll as required
Merge remote-tracking branch 'origin/release/2.47'
Set version to 2.47.02
Changelog updated for v 2.47.2
Git.hub version changed to 0.1.1. Fixes #2124.
Set version to 2.47.03