added regions to elbadmin

Added a --region flag to the elbadmin script so that you could have it connect to regions other than the default.

Old behavior:
elbadmin ls
elasticloadbalancing.us-east-1.amazonaws.com
Name                 DNS Name
--------------------------------------------------------------------------------

New behavior:
elbadmin -r us-west-2 ls
elasticloadbalancing.us-west-2.amazonaws.com
Name                 DNS Name
--------------------------------------------------------------------------------
blah-www-1        blah-www-1-123456789.us-west-2.elb.amazonaws.com