Create CHANGELOG.

Change-Id: I6642fc2c25d13f5633cf9e95f58fa4cf3789c7c9
Release 1.0.0.

* Add `authors.db` database using the `prop=contributors` mediawiki
  API to record article authorship information.
* Add image metadata (artist, credit, license) to image database.
* Add `attribution.html` (and optionally `attribution.wt`) to localize
  attribution credits (generated from the above two databases).
* Use random filenames for images (security improvement).
* Robustness improvements (request timeouts and retries, disable
  request pool, use `readable-stream` on node 0.8).
* Handle protocol-relative urls.
* Performance improvements (skip more unnecessary fetches when
  `--no-compat` is given, increase some request batch size).

Change-Id: Icd4f44b9436116936c2221ecf861726657ac18bc
Bump version after release.

Change-Id: I1ec359d72810410972c6e89b486bb0c63ca5e96f