default the "describe" output mode to "Stack Name" and add an option to display Stack ARNs (-l / --long). Describe now also includes the stack output, which may be useful to reference for other knife commands (e.g.if a stack outputs an ELB DNSName, and another stack uses that as a parameter).
removed "outputs" functionality from describe and moved it to it's own module. updated doc
Merge pull request #7 from brettcave/master

Added "outputs" module, to retrieve the outputs of a stack