Use UserWarning since this is not Python stdlib code.
Don't silently drop the port option, instead use it for the default protocol port. Closes #194.
Merge pull request #194 from basho/gh194-port-deprecation

port argument to RiakClient is "silently" ignored
add bucket property clearing.
updates for comments.
Merge pull request #200 from basho/pevm-clear-props

Allow clearing of bucket properties.