Increment version to 0.5.3.
Start on History.md for 0.5.3.
Spark: Test that patching "<input type=checkbox/radio checked>" onto unchecked
input works.

This test was extracted from a fix for this specific issue #478 which
accidentally never got merged; 442b86eebd ended up fixing this issue with a
slightly different change than the unmerged fix.
Finish first draft of 0.5.3 release notes.
Remove some no-longer-true caveats about Minimongo from docs.
accounts-ui-viewer: use triple-stash for the inclusiong of checked="checked" to
avoid escaping the quotes.
Follow-up to 442b86: fix re-rendering of unfocused radio buttons.

Before 442b86, this worked because we always unconditionally made tgt checked if
src was checked. With the new 3-way-diff algorithm for value and checkedness, we
need to save the checkedness of tgt before any DOM manipulation that could
uncheck it.
Add a script for copying builds from Jenkins to s3.
Merge branch 'devel' into release-0.5.3

This consists of three Accounts-related pull requests, which I will add to
History.md in the next commit.
Updates to History.md from last merge.
copy-release-from-jenkins now takes care of setting URLs correctly in
s3://com.meteor.static/test/update/
Fix lookup by fields beginning with numbers (broken by 2d2aaa808).
Merge branch 'devel' into release-0.5.3

Bring in Meteor.http.call JSON header improvement.
Update History.md.
Re-run app when --settings file changes.
admin/node.sh: Preserve node's exit code.
Make the modification needed for testing the updater simpler.
admin/cli-test.sh --global should use 'meteor' from $PATH, not hardcode
/usr/local/bin.
Make cli-test.sh pass on Linux.
More sleeps to help things work on Linux.