Remove obsolete Aker configuration for CI environment.
Use moment.js for date arithmetic, parsing, and formatting.  #4172.
Default searches to a six week timespan.  #4172.
Make jQuery UI's datepicker enter dates in YYYY-MM-DD.  #4172.

We expect YYYY-MM-DD format, so might as well make the datepicker do
that, too.

It'd be nice to have a single place for date formatting.  It's possible
to do something like this:

    $.datepicker
      onSelect: (date, dp) =>
        @set 'value', moment(date)

but while this does help us maintain a consistent format, it introduces
undesirable visual glitches as the datepicker's value is updated twice
in quick succession.
Work around an odd acceptance test glitch.  #4172.
moment.js-based date validation.
Ensure that the datepicker is initially hidden.
Ensure Model is loaded.

Without this, we occasionally get exceptions like this:

    uninitialized constant Model (NameError)
      app/models/event_type.rb:1:in `<top (required)>'
      app/models/event_type_store.rb:12:in `block (2 levels) in request'
      app/models/event_type_store.rb:12:in `map'
      app/models/event_type_store.rb:12:in `block in request'
      celluloid-0.14.0/lib/celluloid/calls.rb:25:in `call'
      celluloid-0.14.0/lib/celluloid/calls.rb:25:in `public_send'
      celluloid-0.14.0/lib/celluloid/calls.rb:25:in `dispatch'
      celluloid-0.14.0/lib/celluloid/calls.rb:67:in `dispatch'
      celluloid-0.14.0/lib/celluloid/future.rb:21:in `block in initialize'
      celluloid-0.14.0/lib/celluloid/internal_pool.rb:59:in `call'
      celluloid-0.14.0/lib/celluloid/internal_pool.rb:59:in `block in create' (celluloid):0:in `remote procedure call'
      celluloid-0.14.0/lib/celluloid/future.rb:114:in `value'
      celluloid-0.14.0/lib/celluloid/future.rb:78:in `value'
      app/models/store.rb:20:in `all'
Require date entry as YYYY-MM-DD.