ssh tool cleanup

Cleans up SshTool's interface. Deprecates lots of methods, so that we have consistent naming for file/stream copy operations: copyToServer and copyFromServer.

Because this is internal (i.e. in package brooklyn.util.internal.ssh) I don't think we need to keep deprecated methods as long. But probably sensible to delete them in 0.6?

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- Improve method names/signatures in SshTool; deprecate old ones
- Remove some code duplication
- Add test for ssh-key with passphrase
- SshjTool creates temp file for scp'ing, when doesn't know size of InputStream