Adding code for JSch agent proxy integration.

This will allow use of ssh-agent and Pageant SSH information. Initial
work for #24.
Integrating JSch agent proxy support into transport tasks.

This is work for #24. Testing is failing due to ymnk/jsch-agent-proxy#8.
Updating to jsch-agent-proxy 0.0.6 which support 4096 RSA keys.
Final v0.6.0 updates to docs.
Merge branch 'master' into grgit

Conflicts:
	build.gradle