Add get_vapp_edge_public_ip and get_vapp_port_forwarding_rules

The first method allows us to fetch the public IP of a vApp
when using a vShield Edge device to fence it using port
forwarding mode.

The second method returns a vApp portforwarding rules.
Add suspend_vapp method
Add reboot_vapp and reset_vapp methods
Remove trailing spaces
get_vapp_edge_public_ip: improve error handling
get_vapp_port_forwarding_rules: improve error handling
get_vapp_edge_public_ip: don't check if vapp is running

This check is delegated to the user.
get_vapp_edge_public_ip: add tests
get_vapp_port_forwarding_rules: add test
Add upload_ovf public

It uses a private method upload_file that shows progress bar
and puts range upload to minimize upload disruption
Modified README and updated Gemfile.lock
upload_ovf: minor changes