various SSH/shell improvements, based on #837, including:
* PROP_SCRIPT_NO_DELETE not to delete scripts after uploading
* PROP_OWNER_UID to indicate who should own a file being transferred
* lots of code tidies
ensure global brooklyn.properties and config on entity and on locations all get used by ssh commands,
so e.g.  `brooklyn.ssh.config.noDeleteAfterExec=true`  will take effect; also refactoring to make that code and other code tidier
Merge pull request #1071 from ahgittin/feature/ssh-no-delete-and-more

feature - ssh no delete and more