[nemo-qml-plugin-email] Add emailfolder.
Merge pull request #18 from kananoja/master

[nemo-qml-plugin-email] Replacing QVariants with basic types for better QML compatibility
Merge pull request #19 from VDVsx/master

[nemo-qml-plugin-email] Add emailfolder.
[nemo-qml-plugin-email] EmailMessage::setRead added