Abbreviate CHANGELOG.md entry for 1.2.0

It now follows the policy of only documenting user-relevant changes.

CHANGELOG.md

 ## 1.2.0 / 2016-10-07
 
-* [FEATURE] Enable the use of query parameters in `/graph` URLs.
+* [FEATURE] Cleaner encoding of query parameters in `/graph` URLs.
 * [FEATURE] PromQL: Add `minute()` function.
 * [FEATURE] Add GCE service discovery.
-* [FEATURE] Allow job names to start with a digit.
+* [FEATURE] Allow any valid UTF-8 string as job name.
 * [FEATURE] Allow disabling local storage.
 * [FEATURE] EC2 service discovery: Expose `ec2_instance_state`.
-* [FEATURE] HTTP basic auth and TLS support for remote write path.
-* [FEATURE] Support for relabelling in remote write path.
-* [ENHANCEMENT] Add `go_import_path` to Travis so it works on a fork.
-* [ENHANCEMENT] Makefile: Promu installation now logged.
-* [ENHANCEMENT] Fingerprint locking: Avoid having contended mutexes on
-  same cacheline.
-* [ENHANCEMENT] Avoid slow `defer` in the `seriesMap.get` hot spot.
-* [ENHANCEMENT] Improve label matching performance.
-* [BUGFIX] Fix word alignment of struct fields in tests.
+* [ENHANCEMENT] Various performance improvements in local storage.
 * [BUGFIX] Zookeeper service discovery: Remove deleted nodes.
 * [BUGFIX] Zookeeper service discovery: Resync state after Zookeeper failure.
 * [BUGFIX] Remove JSON from HTTP Accept header.
-* [BUGFIX] Update govalidator vendoring to fix URL validation.
-* [BUGFIX] Fix race between reload and stop of the rule manager.
+* [BUGFIX] Fix flag validation of Alertmanager URL.
+* [BUGFIX] Fix race condition on shutdown.
 * [BUGFIX] Do not fail Consul discovery on Prometheus startup when Consul
   is down.
 * [BUGFIX] Handle NaN in `changes()` correctly.
-* [CLEANUP] Remove DNS resolution dependency from tests.
-* [CLEANUP] More tests for PromQL time functions.
-* [CLEANUP] Add contexts to PromQL and storage interfaces.
-* [CLEANUP] Consolidate web API contexts. Update `common/route` vendoring.
-* [CLEANUP] Storage: Chunk code in own package. Added Utilization method.
-* [CLEANUP] Export various identifiers for better code reuse.
-* [CLEANUP] Cleanup code issues reported by goreport and added link to
-  goreport in README.md.
-* [CLEANUP] Various other minor code cleanups and fixed typos.
-
-Below changes are not considered breaking because they affect parts marked as
-experimental or unstable:
-
-* [CHANGE] Remote write path does not use gRPC anymore.
+* [CHANGE] **Experimental** remote write path: Remove use of gRPC.
+* [CHANGE] **Experimental** remote write path: Configuration via config file
+  rather than command line flags.
+* [FEATURE] **Experimental** remote write path: Add HTTP basic auth and TLS.
+* [FEATURE] **Experimental** remote write path: Support for relabelling.
 
 ## 1.1.3 / 2016-09-16