Now editing the color from the theme affects the bubbles directly. Monochrome versions left to do still. Also added the Theme entries so the theme applies to the bubbles

This is the first feature to hardcode cheogram.com let's hope we can remove it
someday.

XEP-0033 does not have good fallback behaviour, and group text doesn't map well
to MUC.  We could still do a MUC mapping, or think of a better fallback
behaviour, or something else, but for now analysis paralysis means we stick to
the gross +1...,+1...,+1...@cheogram.com -- but that's not a protocol, it's not
something we can detect or design around or expect anyone else to ever do.  So
just check for cheogram.com because that's the only place we ever expect to see
this dirty hack.

If starting a new private group and every selected member is @cheogram.com, then
ask if we should make a group text instead.

For debugging call connections etc.

A body that is present but has an empty string is not the same as no body.  It
may be useful for example for a message correction to an empty string.

So if someone else sends one to the bare JID, we should deliver it to any
connection that matches.

* content-addressable:
  Content Addressable Media Storage

* commit 'cb0442b84a0b40bb58b0741c420970ba07c1a889':
  Tag navigation UI

This allows delaying to, eg, submit a form or otherwise.

Downloads are stored at a filename that is the CID computed from a SHA256 hash
of their contents.  Where necessary (such as to stream a large file down) they
are stored at the name based on the message UUID temporarily and then renamed.

Uploads, when they must be copied into our storage, are stored in the same way.

This results in de-duplicated storage, so sending the same file back and forth
many times even in different conversations results in only one copy being
stored.

Since Android does not play nice with symlinks, but we want to be able to look
up media by multiple possible hashes, the CIDs for SHA1, SHA256, and SHA512 are
all stored in a new database table whenever a file is downloaded or uploaded,
even if the file is never copied into our storage at all (so then the db table
contains a path to, say, the image in the camera folder).

When bits-of-binary cid transfer is attempted, first check if we have that
content locally already and just use it if we already have it instead of
requesting it again.