Opts and Desc separated, no MustNew except MustNewConstMetric.

Change-Id: Ia64ef0fc5181f27c9b0ca034a5f7ef8deb78b70a
Use chan for collector descs.

Change-Id: I813589f8a94098d386a50cded6929f65c168eadd
Implement desc.String().

Change-Id: Iccf6f1a56065407e8a27bfe5859bd488b76fd2c0
Doc comments for Opts.

Change-Id: Ia9027fff031b2709cbe52d8a8ddb9caa15929b5e
Example for SelfCollector and user-defined Metric.

Change-Id: I096968fd710772056ed9b5a3f35fbf7f8e8ede30
Fixed and improved InstrumentHandler.

Change-Id: I48512dc9417301816ffc79f2d497430cec6aed66
Consistency checks upon scrape.

Change-Id: I201c6e96f2ce776773cc5be772ee652edca09dde
Streamlined metric family injection hook.

Change-Id: I44397430c723c0e35723d3f54bc4639dafc7533a
Makefile and doc cleanup.

Change-Id: I035359ad868efc14d6ed066c54262e3411bde35b
Fix protobuf accessors.

Change-Id: I31b9ff6bb87e82685b782982eaf6dcaece505e44
Some minor TODOs done.

Change-Id: I1c9225f002ec4a84b84dfe2a9e0ae4161fc7aef7
InstrumentHandler test, fixed summary.

Change-Id: Ie0e034f22af64b8d3835d9aaabdecd1928d49225
More doc comments, tests, testing by example.

Rename canonical name -> fully-qualified name everywhere.

Change-Id: I3870a75f933e2840abd8ffdbfbb99fad277a8030
Major imrovements to summaries.

- various fixes
- switched to new quantile package
- more tests
Enable collect checks in handler test.

Change-Id: Ifcb15139fa725f9e65c6de05d193d22f9ee42049
More vec tests.

Change-Id: I4430a5932d5c73cb6e212abd1ada16cc61763c52
Restructured tests and examples. Many more doc comments.