Add SmartGit's git, ssh and other unix utilities to Windows PATH as part of the installer

Making it easy to add the git, bash, ssh and other utilities to the PATH of the Windows machine where SmartGit is installed

We have users that also install “Git for Windows” and then use that for command line git – which can lead to different version of git with different setups leading to problems.

If the SmartGit installer could just register its directories on the PATH then people would only have to install one tool.