Search git and git-lfs via locate function

[uenz]

SparkleShare uses several comandline tools to provide functionality. While working on the windows version i saw that git path was hard coded and git-fls is copied to a BinPath in personal folder. With the extension to the Locate function, it is possible to hand over platform specific search pathes. With this modification the BinPath is no longer necessary anbd the platfrom dependance of Git.Fetcher and Git.Repository is no longer required.