[nemo-qml-plugin-email] Improve standard folder handling for trash folder.

Change default account sync to -1 since QMF can return 0 for invalid accounts.
Merge pull request #66 from nemomobile/local-folders

[nemo-qml-plugin-email] Improve standard folder handling for trash folder
[nemo-qml-plugin-email] Improve folders model to handle local folders properly.
Merge pull request #67 from nemomobile/standard-count

[nemo-qml-plugin-email] Improve folders model to handle local folders properly.
[nemo-qml-plugin] Send messages in outbox when syncying the account.

Introduce sendMessages invokable.
Merge pull request #68 from nemomobile/vdv-devel

[nemo-qml-plugin] Send messages in outbox when syncying the account.
[nemo-qml-plugin] Initial test cases for EmailFolder and EmailMessage
[nemo-qml-plugin-email] Improve message replies and forward

References headers added for better conversation support
Merge pull request #70 from nemomobile/reply-fixes

[nemo-qml-plugin-email] Improve message replies and forward
Merge pull request #69 from nemomobile/test-cases

[nemo-qml-plugin] Initial test cases for EmailFolder and EmailMessage
[nemo-qml-plugin-email] Add missing plugin.
[nemo-qml-plugin-email] Don't enqueue export updates twice.

Emit count changed when folder or account key changes in emailmessagelist.
Merge pull request #72 from nemomobile/delete-improvement

[nemo-qml-plugin-email] Don't enqueue export updates twice.
[nemo-qml-plugin-email] Add mutipleRecipients property.
Merge pull request #73 from nemomobile/mutiple-recip

[nemo-qml-plugin-email] Add mutipleRecipients property.
[nemo-qml-plugin-email] Improve multi (de)selection.
Merge pull request #74 from nemomobile/multi-selection

[nemo-qml-plugin-email] Improve multi (de)selection.
[nemo-qml-plugin-email] Support delete from mutiple accounts.
Merge pull request #75 from nemomobile/delete-multiple

[nemo-qml-plugin-email] Support delete from mutiple accounts.
[nemo-qml-plugin-email] Remove qt4 support

QMF upstream dropped qt4 recently, so we need to do the same here
in order to be in sync.