Import calendar title form iCal files. Fix #111 and Fix #123 (again)

Add no description placeholder on events without descriptions. Fix #123
Use calendar name of iCal file to prefill calendar name on imports, use cozy-ical 1.1.4 .
Fixes in sendmail confirm, during import and to maintain sending email list accurate with mails actually sent by the server.

Fix tests and avoid rebase messup of previous PR.
Yes, but in that case, the `startDateChanged` is checked in the function before. This change leads to the following: if you remove the event, and the user has accepted, it is not notified.