refactor preferences into multiple PreferenceFragments
Add k-9 style avatars to group conversations

Closes #1107
Support localization in passphrase activity and lock notification.

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Closes #1328
Enable progress indicator on group update

Closes #1165
Add option that allows disabling MMS fallback with TS users.

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Closes #1444
Support for ShortcutBadger

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Closes #1574
Closes #1952

Fixes #1526
Fixes #321
Show drafts in conversation list snippets

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"add contact" button for unknown contacts

Closes #1551
transport selection refactor

Closes #1724
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remove workaround for nested PreferenceScreen's

Closes #2208
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Add support for notification reminders.

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Closes #1623
Fixes #323
minor preferences tweaks

1) shorten some summaries
2) add summaries to appearance subscreen
3) move common summary functions to common parent class

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another minor pref tweak for mms fallback

1) fix summary for outgoing sms/mms
2) disable mms option when TS-users is unselected, same as the fallback
   approval option.

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update build tools

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Switch to forked ShortcutBadger.

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whitespace cleanup

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Closes #1779
Enabled audio and video drafts

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Closes #1799
Use betterpicker for HMS timeout.

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Closes #1890
Update min/max fix in shortcutbadger

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Fix user-facing helping term 'insecure' to 'unsecured'.

Insecure implies an uncertainty of intention or confidence.
Unsecured is more specifically addressing the protocol which
wraps the message delivered.

Closes #1811