Disable touch callout and selection in UI

Disable WebKit touch callouts and disable selection for copy/paste
at the body level -- does not affect input fields.

Multiple sources suggest this for PhoneGap applications, and it does
seem to have a positive benefit in this app. We may consider adding
selection back for some specific elements at a later time.

Signed-off-by: Jeff Godin <jgodin@tadl.org>