* [x] explain semver since this upgrade cases are when this applies
* [x] links to different parts of manual
* [x] move backup section to the top
* [x] add "real" git pull example
* [x] rename install script to plain ./install
* [x] remove very old monit upgrade help
I tried to only merge what makes sense for us, there is still quite some cleanup needed, this commit tries to preserve the 2.5 manual as much as possible while still keeping the rare new stuff from pro.
ryan
Lucas Bickel