Add test for sending double values for gauges
Overload gauge methods to send either longs or doubles
Merge remote-tracking branch 'upstream/master' into double-gauge
More Tests for Gauges

* Test that a gauge of 0 sends a zero and not a zero delta
* Test that double values of high precision are sent properly
Use common method to handle logic of sending gauges
No longer using DecimalFormat
Fix JavaDoc from convenience methods
Add new test for large fractional gauge values
Explicitly format long and double values for gauges
add missing JavaDoc for new gauge methods taking doubles
avoid formatter usage for long values
minor efficiency gains
move method up, for clarity
Merge pull request to support double values for gauges, with some minor tweaks -- references #23 and #19.