Bug 878820 - Contacts imported from VCF files disappear [r=arcturus]

[sergi]

• Using mozContacts now
• Isolated functionality to make it easier to test
• Added Unit tests
• Not considering 'photo' field

[sergi]

In the previous review of this issue, there was an error with photo fields. It turns out that all the API docs and tests in Gaia (!!) are doing the wrong thing when assigning values to the photo property of a mozContact object. The value of photo HAS to be a Blob, and not a String. Upon pointing this out, some API docs have been corrected, but many tests in Gaia are not (yet).

Since there is another issue regarding Vcard photo import (https://bugzilla.mozilla.org/show_bug.cgi?id=885545), I will tackle that one and add photo importing there. For now, photo importing for the contact is disabled since it was wrong anyway.

/cc @arcturus

[arcturus]

Test for vcard passing for me locally.

Code already reviewed, r+

Thanks @sergi for the work!