Use "date sent" as timestamp for push, "date received" for SMS.

The "sent time" is not reliable on SMS messages.  This switches
to using "sent time" by default for push messages, but "received
time" for SMS messages.
Reword the very confusing screen security setting
reorganize readme

// FREEBIE
Better share intent handling.

1) Guess mime type from share intent EXTRA_STREAM uri.

2) Always include EXTRA_TEXT (if present)
Add notification for key change event.

Fixes #1460
Sort contacts case-insentively

This fixes the case sensitive ordering of contacts in the view
for creating new conversations.

Fix #1502
Show drafts emojified when Android version is below KitKat
Remove directory refresh preference.

This is present on the contact screen now, so there's no longer
any need for it here.
Improved the warning icon: Higher resolution, better size.
Use contextual action bar menu for conversation items.