Wavefront Libraries 4.27

Proxy: gzip compression for sending metrics to Wavefront is enabled by default
Proxy: support variable sampling rate for logging valid points
Proxy: fixed bug with Graphite 1.1 format tags
Proxy: reduce scheduler overhead when draining buffers under heavy load
Proxy: enable --help command line option
Proxy: support both \u2206 and \u0394 markers for delta metrics
Proxy: block negative values for delta metrics
Proxy: trim token and server config properties
Proxy: remote shutdown sequence bug fixed
Proxy: don't log API token details during installation
yammer-metrics: emit timestamped metrics
yammer-metrics: reduce overhead when sending empty histograms
dropwizard-reporter: emit timestamped metrics
dropwizard-reporter: sanitize metric names