CCI Commands which require an id now take 'identifier'

CLI: Now instead of requiring the user to remember or copy/paste numeric ids
     everywhere in the CCI-related CLI commands, you can now pass in hostname,
     public ip, private ip or, of course, the numeric id of the CCI.

     If no CCIs match, an error is returned.
     If more than one CCI matches, an error is returned with the list of relavent ids.

Examples:
    sl cci detail production
    sl cci dns sync devapp01
    sl cci reboot 12.34.56
    sl cci shutdown 12345
Creates IdentifierMixin Class

API: Moves the layered identifier logic into a mixin to be used in other manager
     classes. Provices the resolve_ids() method which tries to coerce the given
     identifier into an id using methods (in order) defined in the 'resolvers' attribute.
The new mixin lives in SoftLayer.utils
Fixes multiple inheritance issue
Merge pull request #77 from sudorandom/identifier

CCI Commands which require an id take 'identifier'