added support for sets
Set elements are no longer automatically aggregated but rather sent as individual packets.
Merge pull request #5 from danieltwagner/master

Add support for sets
tomd: correct whitespace following merge of pull request
tomd: make test class final
tomd: better name for set value parameter, and better JavaDoc
tomd: correct incorrect parameter name in interface definition
tomd: extract superclass for convenience methods to make the implementation class cleaner and more focused
tomd: correct bug with setting gauges to negative values
tomd: extract common code for message construction into a method
tomd: whitespace
tomd: extract common test setup
tomd: support empty or null prefixes -- fixes #8
tomd: add support for gauge deltas -- fixes #6
tomd: change to use longs instead of ints -- fixes #11
tomd: create convenience method allowing the user to record the completion of a timing event that finishes now -- fixes #13
tomd: update JavaDoc for set support
tomd: use a daemon thread so that JVM shutdown is not prevented -- fixes #7
tomd: support sample rates for counters, for issue #10
tomd: support sample rates for counters -- closes #10