Properly convert html to text

make composer view reusable, reply IMAP drafts, mailto IMAP drafts, reply attachment

Fix sending replies from unified inbox

Display inline images - fixes #138

enable HTTP caching for HTML message bodies

PHP variables start with a $ 😉

increase max-version to 8.2

unified inbox: respect 'count' parameter and return only the first 'count' messages

partially fixes #803

fix PHPDoc parameter types for proper casting to bool/int

Increase timeout

Ref https://scrutinizer-ci.com/g/owncloud/mail/inspections/322529f7-f4f8-4f6e-8c17-6e428b2c7452

Introduce php mail as alternative transport

don't show subject for replies; fix reply body errors

use object literal to extend Backbone view - fixes shared private property problem; expand reply composer on click

basic IMAP reply drafts added

use backbone $ selector; fix submit button text; disable reply drafts

show reply to/cc/ccList correctly

fix attachments for new messages and replies

enable reply drafts again

fix concurrent view events

fix deletion of previous reply drafts

generic reset, send and draft

adapt classes/IDs

rename file

fix html classes

fix CSS selectors

fix cc/bcc toggle; fix travis errors

add draft UID; fix missing BCC

 Fixing Logger implementation to implement ILogger + fix smtp auto conf in case of php mail() is used

Remove CSRF token

We now rely on CSP instead of sandboxed iframes. Partially addresses #767