Assorted fixes.

Default to displaying all contacts rather than none as it's confusing
and a litte error prone that the model displays nothing without setting
a filter.

Don't ignore results from refreshed updates, and fix errors not caught
because that wasn't happening.

Use the custom label from QContact if a first/last name isn't available
before falling back to an alternative.

Resolve names from IM accounts correctly in sparql query.

When querying for favorites, test the value not just the existence of
the property.

Fallback to the imAvatar if there is no photo for a contact, and emit
dataChanged if the url for an avatar has changed.
Merge pull request #87 from chriadam/master

Add arbitrary request API to SocialNetwork adapter
[Email] - Add lastUpdatedAccountTime() binding.
Merge pull request #90 from VDVsx/master

[Email] - Add lastUpdatedAccountTime() binding.
Merge pull request #88 from adenexter/contacts-fixes

Assorted fixes for nemo contacts plugin
Ensure time is updated when WallClock is enabled
Merge pull request #91 from martinjones/master

Ensure time is updated when WallClock is enabled
Expose contact presence state
Add test for presenceState
Merge pull request #92 from matthewvogt/presence

Expose contact presence state
Add folderUnreadCount binding.
Merge pull request #93 from VDVsx/master

Add folderUnreadCount binding.
Check for valid ID before returning a person instance
Merge pull request #94 from matthewvogt/contact-id-validity

Check for valid ID before returning a person instance