[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"


worth adding comments that:
* this is deliberately not `Os.tmp()` as it is the target machine
* explain what the `r` at the start does
* clarifying that in normal operation it should never get picked up because `ONBOX_BASE_DIR` will be set