admin orders - enhancement to action button

The action button, used for bulk editing orders, will no longer appear
until at least one order is selected.

When an order has been selected, the button will appear and 'highlight'
to draw attention to it.
admin orders - bug and style adjustment to send mail

The 'send mail' portion of the button had stopped triggering the down
arrow button click event when pressed, so it appeared to do nothing
(unless you clicked the down arrow).  This is fixed.

adjusted the css on the dropdown itself to look nicer and be less likely
to wrap.
admin orders - adjust verbage on email list

Made all of the email message prompts use new case styleguideline (first
word capitol only) and changed the verbage on the custom to custom/edit
so it would be more clear what the button can do.