I'm glad to present you a program I made, it's called "Garry's Mod Manager".
First released 2010 (only in German) there were many Versions of this program.
But now there is finally a english one, which I want to show you here.
First of all, a Screenshot:
BUT, what is this for?
Like its name, this program is made to install addons, update them, manage and more.
You can also install maps, dupefiles, gamemodes and got it? Manage them :P.
It replaces Tortoise SVN, a own SVN-Client is fully integrated.
I made a Tutorial, but its not the best, because i'm german and my english sucks :):
But i hope it can help you to understand how to use it.
(May someone could help me making a better english one?)
The Program can be directly downloaded here: http://lansoftware.org/Garrys%20Mod%...er%20Setup.exe
(.NET Framework 4 is required and will be automatically installed.)
Greetz and have fun!
If you want to join it's Steam-Group, go there: http://steamcommunity.com/groups/GmodManager
Want more? Visit my Website: http://www.lansoftware.org (but there's not much content yet :P)