[nemo-qml-plugin-email] Insert inline image asynchronously when they bec...

...ome available.
Here: https://github.com/nemomobile/nemo-qml-plugin-email/commit/0eafb5abbe17b8959e31faf0a79e4bbf079f083d

Some of the are QByteArray so is better and safer to use fromLatin1.