Updated gitflowtool.txt to provide more instructions. Please keep this file for reference.

If you are working on my (mats) server, you have git-flow already installed.  If you are working on your own computer, I suggest using sourcetree or using this tool from the command line.  Sourcetree is great but unfortunately it is not available for linux.  Please keep this file here for reference. I'll update it as I discover more git flow usage scenarios.