v0.8.0

* Make the http client retry 50x (Netflix#76)
* Add spectator.registrySize (Netflix#75)
* Add Measurements callback mechanism to Registry (Netflix#74)
* Only reset gauge values after expiration (Netflix#73)
* Do not copy the shared_ptr in insert_if_needed (Netflix#72)
* Registry name/tags convenience overloads (Netflix#71)
* Add support for eager percentile metrics (Netflix#70)
* Update gtest dependency (Netflix#69)
* Minor update to benchmark for tables (Netflix#68)
* Keep track of invalid measurements (Netflix#67)
* Fix flaky http_client post test (Netflix#66)
* Avoid common_tags lookup in append_measurements (Netflix#65)
* Make registry.Size thread safe (Netflix#64)
* Cache Ids used in measurements (Netflix#63)
* Wait one interval before running expiration tasks (Netflix#62)
* Helper to get the number of meters in the registry (Netflix#61)
* Use best_speed compression (Netflix#60)
* Automatically Stop the registry (Netflix#59)
* Expire inactive meters (Netflix#58)

v0.7.9

Faster implementation for the meters map in the registry (using tsl::hopscotch_map)

v0.7.8

* Automatically call `Stop` on the publisher in case the user failed to do
so.

* Fixes for OSX bazel build

v0.7.7

Support for bazel on OSX

v0.7.6

Do not use libcurl PUT helper. Just the simple custom method option

v0.7.5

Support for HTTP PUT

v0.7.4

Support custom headers in HTTP GET requests

v0.7.3

Retry 503s and 429s

v0.7.2

Fix some deprecation warnings

v0.7.1

Clean up of the HTTP client