ewma: ensure 64-bit alignment of uncounted

This bug was already fixed by #20 (and reported in #19) but was rolled
back after merging #17.

`uncounted` has been moved to top with a comment explaining that it
should stay at top. This is not mandatory but this is the easiest way to
ensure a good alignment in the future without taking too much care.

This alignment is required to use atomic functions as explained here:
 http://godoc.org/sync/atomic#pkg-note-bug
Merge pull request #37 from vincentbernat/fix/atomic-alignment

ewma: ensure 64-bit alignment of uncounted
Add influxdb backend
Merge pull request #38 from crosbymichael/influxdb-backend

Add influxdb backend
Update README.md
initial implementation of GaugeFloat64
Rework NumGC and PauseNs runtime metrics.

Fixes #41.

@majek is right that numGC not being updated breaks the PauseNs
histogram pretty badly.  What's more, the simplistic bridge between
runtime.MemStats and go-metrics was unable to cope with a couple of
obvious possibilities like wrapping PauseNs and more than 256 GCs since
the last metric update.
Merge branch 'feature/GaugeFloat64' of git://github.com/daniel-garcia/go-metrics into GaugeFloat64
Tidying whitespace.
s/GaugeSnapshotFloat64/GaugeFloat64Snapshot/

This name is more consistent with the rest of go-metrics.
Do not export methods from sync.Mutex on gauges.
Merge branch 'patch-1' of git://github.com/lidashuang/go-metrics
Allow lazy instantiation of metric in GetOrRegister.

Fix also memleaks in GetOrRegister* due to this
non-lazy instantiation.
Merge pull request #45 from laurent-descrivan/master

Allow lazy instantiation of metric in GetOrRegister.
Tidy up name and whitespace.
Use a single goroutine for meters.

Update meters to create a single goroutine responsible for ticking all
of the meters.
add opentsdb support
Return an error from Register and disallow dupes

This is a change to the interface that will appear as a breaking change
for authors of Registry implementations.  The change was made in support
of the change described below.

rcrowley/go-tigertonic#60 points out that metrics can be reregistered
causing the original metric to be lost.  This patch change the Registry
interface's Register method to return an error and implements this
change in StandardRegistry.Register and Register.
StandardRegistry.Register (and therefore Register) returns a
DuplicateMetric error if a name is already registered.
Style.
Merge branch 'issue-40'