Remove extraneous onChange

This method wasn't being used anywhere.

Change-Id: I874ee4165802803813928f15a4df7d6921fe4db9
Reviewed-on: https://gerrit.causes.com/19291
Reviewed-by: Alex Wallace <alex.wallace@causes.com>
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>
Tested-by: Tony Wooster <tony.wooster@causes.com>
Remove redundant setting of input value

The input element's value was being set immediately before a
subsequent call would re-set its value. This commit removes that
redundant initial call.

Change-Id: I93d2f6eb5d4f37a81ff1289ae179efccb9588ec1
Reviewed-on: https://gerrit.causes.com/19292
Reviewed-by: Alex Wallace <alex.wallace@causes.com>
Tested-by: Tony Wooster <tony.wooster@causes.com>
Add `onActivate` callback

This commit adds an `onActivate` callback, which is triggered when the
user activates -- via mouse or keyboard -- an item in the autocomplete
list. This allows a little bit more customization for autocomplete
fields that behave more like inline-search where replacing the value
of the input element is undesirable.

This commit also fixes a bad interaction between `isSelectable` and
`autoSelectFirst`, whereby the first item in the list would be
selected regardless of its `isSelectable` status.

Change-Id: Ia7886314cb6827bce04bb94cd325f706e707bdc7
Reviewed-on: https://gerrit.causes.com/19293
Reviewed-by: Tony Wooster <tony.wooster@causes.com>
Tested-by: Tony Wooster <tony.wooster@causes.com>