Use visitor pattern to create conversation items

See merge request !933

Upgrade the gradle wrapper to version 4.10.2

See merge request !932

Use ConversationManager for private message retrieval

See merge request !912

Fix app lock after sign-out bug

Closes #1386

See merge request briar/briar!930

Remove AndroidHttpClient class after Roboelectric update

See merge request !929

Add support for right-to-left languages

Closes #1378, #1076, #1078, #964, #1080, and #1079

See merge request !918

It some cases, it was observered how the app was locked after the user
had signed out.
This commit ensures that set alarms are canceled and that no new ones
will be set after the LockManager service has been stopped.

Fixes #1386

If no contacts exist, at least one will be created

to prevent it from being pushed off-screen

Fixes #1076

Fixes #1078

Also fixes several small UI glitches with long texts

Adds RTL support
Fixing cropping bug

Closes #964

Adds RTL support
Fixes issue with long contact names

Closes #1080

Adds support for RTL languages
Fixes issues with long contact names

Closes #1079

Rename "Screen lock" to "Lock app"

Closes #1248 and #1245

See merge request briar/briar!924

Remove lockscreen notification setting

Closes #1186

See merge request briar/briar!925

Align "decrypting database" message to centre

See merge request briar/briar!926

Add obsolete fingerprint permission to satisfy Android Studio

See merge request briar/briar!927

Fix off-by-one error in expiry calculation

Closes #1384

See merge request briar/briar!923

Allow retransmission if it will result in faster delivery

Closes #541

See merge request briar/briar!908