Instead of blocking the message queue when we don't have a session, we instead just send out a session request and send the queued messages using fallback encryption.
This means that users will be able to message right away without having to wait.
The only down side is that all messages sent before sessions are established will be using the weaker encryption.
This change also means we have to detach session requests from envelope type (which is a good thing) and thus now a message is a session request if it contains a preKeyBundle.
* textsecure/master: (26 commits)
v1.21.0
v1.21.0-beta.4
Dark Theme: Preserve blue background on app loading screen
Localization updates
Fix width of audio player when window is very narrow
A number of small fixes for Link Previews
Get rid of the white flash when the app starts up (#3083)
v1.21.0-beta.3
Lint fixes
Introduce new language: NB
Fail over to all numbers in retry if errors don't have numbers
Use the proper method for pulling attachments off disk for retry
Fix rendering bug with verified state in updateVerified()
Update electron-builder and electron-updater
Ensure that dialog pops up when permissions denied for voice note
Lint fixes
Large update to localization strings
Link Previews
Ensure that blocked messages are dropped even after sealed sender
Don't linkify quoted message contents
...
# Conflicts:
# .github/PULL_REQUEST_TEMPLATE.md
# _locales/cs/messages.json
# background.html
# config/default.json
# index.html
# js/models/conversations.js
# js/modules/web_api.js
# js/settings_start.js
# js/views/conversation_view.js
# js/views/settings_view.js
# package.json
# protos/SignalService.proto
# stylesheets/_index.scss
# stylesheets/_settings.scss