support tor everywhere

this changes all api calls to respect the flags for tor and tor-port

• config now has TorPort method to return flag value if set, or default
• api now only has newClient, this creates a tor client when flag is

present. does not need to be exported anymore

• no methods take a tor argument as no longer needed
• all commands now share the same behaviour logging tor messages
• api.torClient was removed as not used anywhere
• all calls to api.newClient now check for and return the error
• api.HandlePost was removed as redundant of api.DoPost