Microsoft EWS Integration with phpEWS library into [mail] app

[filkaris]

This is the first version of the integration we talked about.

The Integration essentially creates a new type for "imap" accounts, which uses Api\Mail_EWS instead of Api\Mail.

Api\Mail_EWS implements Api\Mail's functionality.

There are also a few more classes added. In some case we implement empty functions, just because they are needed by the system in the IMAP cases.

Unfortunately Api\Mail and class.mail_ui.inc.php were not completely separated from the IMAP logic and the Horde objects, so we did the best we could to keep the system functional in both cases with minimal changes.

There is a lot to cover and we'll be here for any additions/changes needed.

[filkaris]

@hnategh @ralfbecker

Did you have a chance to take a look at this? It's a good chance to investigate this soon since I am still actively working on it, and it's all still fresh in my mind.

If more time goes by, I might not be able to support this as easily, since we will be wokring on other parts of the software.