New Commands + better auth options

New get commands:
 * raxmon-alarms-get
 * raxmon-entities-get
 * raxmon-checks-get

Auth Features:
 * Added token auth --auth-token. Requires --tenant to generate correct API uri... this bypasses auth calls so things are much quicker, and allows an admin to use an impersonation token to perform admin api actions.
 * Revised auth credential validation code to simpler and more clear.

Other Stuff:
  * Added --uri and --managed to raxmon-entities-update for managed actions.
  * Better exception handling for errors, nice printing of error code and api messages with stack trace only on --debug or huge errors.
  * New print_item function for printing a non list.
  * Filter by check_id in alarms-list. This isn't supported through the api, only client side filter. But makes it nice for digging for alarms for a specific check when there are lots of objects.