readme: fix indent

Support for grouping notifications with thread-id (RobotsAndPencils#95)

* add: support for grouping notifications with thread-id

* fix: indent

Merge pull request RobotsAndPencils#75 from RobotsAndPencils/wait

calling code needs to ensure all responses are handled (not just received)

go back to using Client.Do (RobotsAndPencils#73)

ref RobotsAndPencils#72

parse GOAWAY error responses from Apple (RobotsAndPencils#71)

with latest x/net/http2.

add collapse id for notification management (RobotsAndPencils#68)

ref RobotsAndPencils#62

Close responses channel when done (RobotsAndPencils#58)

closes RobotsAndPencils#56

Send multiple notifications concurrently (RobotsAndPencils#54)

* example of sending notifications concurrently

* push: build a worker pool into Service

* push: remove version of Push that does serialization

and update docs

* push: reorganize

* push: separate queue type for async

and improve handling of command line flags

* test queue push

(not sure how useful this test is)

don't extract topic automatically (RobotsAndPencils#51)

ref RobotsAndPencils#50

NewService API, simplify certificate loading and pushpackage signing …

…APIs. (RobotsAndPencils#47)

* NewService API extracts topic from cert
* pushpackage: use TLS cert for signing simplifying API for signing and certificate loading
* push: reorganize code, light refactoring