Ability to backout of a command

The prompt should have the ability to cancel an action. In some cases you can get into situations where the prompt is blocking, but there is no possible correct input, and you can't get out of the prompt.

For example when installing new maven dependencies the prompt will display a list of versions. If this list is empty, there is no possible correct value to get to the next step. In a normal shell you would type ctrl-c to cancel a command, but that would close Forge in this case. We need something like ctrl-c within Forge.