Added suffix parameter

Added a statsd suffix that works just like the prefix, but appends to the metric's key instead
Added tests
Updated documentation
Adding the 'set' data type to the client
Adding documentation for the set type
Testing non-integer values for the set data type
Adding reference for the set function; updating wording for the Set type reference
Version bump 2.0.2
Merge remote-tracking branch 'ustudio/master'
Merge remote-tracking branch 'spil-jasper/master'
Revert "Added suffix parameter"

This reverts commit 3c4ec687273416b355c20282e33249d87cd84b52.

Given graphite's support for wildcards anywhere in the chain, this is an
unnecessary complication. The same thing can be achieved with the
prefix, e.g.:

    >>> import socket;
    >>> host, _, _ = socket.gethostname().partition('.')
    >>> prefix = 'my_app.' + host
    >>> client = StatsClient(prefix=prefix)

Stats can be accessed in aggregate as 'stats.my_app.*.whatever.stat'.
merge from upstream