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.
use apply for preferences instead of commit

// FREEBIE
Fix for broken build (*ahem* @phenx-de *ahem*)  =)

// FREEBIE
Add preview of encryption channel in compose text hint.
Add "%s selected" subtitle to Conversation List batch mode.
Correct contextual send language.

1) Use "secure" and "insecure" vs "encrypted" and "unencrypted.

2) Use MMS instead of SMS where appropriate.

Fixes #1602
Validate MMS delivery destination.

We can't depend on validated Recipients anymore, so this adds
parity to the validation the SMS transport does now.

Fixes #1592
Fixes for outgoing SMS/MMS direct and fallback behavior.

1) Correct MMS fallback settings.

2) Prevent SMS/MMS messages from leaking out under certain
   circumstances when they shouldn't.
Fix UI side of broken MMS fallback.

1) Actually tell the SendReceiveService to send the MMS if it is
   one.

2) Display the correct string (SMS vs MMS) in the fallback dialog.
Fix the "Tap for X fallback" labels.
Fix more leaked service connections

PassphraseRequiredMixin might check for a bound service at a time where
the bind has been requested but the service connection has not been
established yet, and therefore fail to call unbindService, leading to a
leaked service connection. This fixes #1518.