Add verbose output to all stat commands

When you stat a container or object with the verbose flag the full path of the
reousrce will be displayed with the token similarlly to how an account stat
displays the auth url and token.

 * move some logic out of bin/swift.st_stat to test it
 * new module swiftclient.commnad_helpers for code you want to test
 * moved prt_bytes into swiftclient.utils to test it
 * fixed IndexError with prt_bytes on sizes >= 1024Y

Change-Id: Iaaa96e0308b08c554205b0055b8a04de581fefa4
Merge "Add verbose output to all stat commands"