[WIP] Fixes for "deploy from Windows"

The changes necessary to get brooklyn-sample running on Windows. Must be started with "-Djava.io.tmpdir=C:/temp"


rename `isAbsoluteHere` to prevent confusion where "local" can mean local (ie non-absolute) directory ?

also do you think it's really worth having these three methods, versus the previous check which while sloppy was simpler and would only break in very weird cases where a directory name started with `X:\\` ?