notifications improvement

fixes #495 and replaces notifications with the native tag feature instead of closing and reopening notifications.
ignore OS X .SD_Store system files
implements #575

this is the implementation of #575
fix for my mistake

I'm sorry, I made a bad mistake and put the line which defines the contacts array also in the if block. Of course this breakes the images_ids reques since it receives a undefined array. >.< This fixes it, I tested it properly.
clean up
css fix
Display both the nick and tel-number in group chats if the contact is
not known. This also modifies how names in general are displayed: the
first 2 components are now shown in full and any further components
are abbreviated.
Add configuration for nick in WhatsApp, fixes issue #512.
WhatsApp: refresh list of group participants when we get a
notification of group participants being added/removed, issue #580
better and shorter pulse

after the feedback from @cmeerw I took an additional look at the CoSeMe library and I found the pong feature to keep the stream alive. I changed the pulse to send a pong. In addition I moved the pulse from the account into the CoSeMe connector. I think this is better now.
avoid multiple pulse intervals
extend the settings not override them
Merge pull request #579 from TitanNano/dev

fix for my mistake
Merge pull request #578 from TitanNano/notify-fix

notifications improvement
Merge pull request #581 from cmeerw/fix-for-issue-557

Display both the nick and tel-number in group chats...
Merge pull request #582 from cmeerw/fix-for-issue-512

Add configuration for nick in WhatsApp, fixes issue #512.
Merge pull request #583 from cmeerw/fix-for-issue-580

WhatsApp: refresh list of group participants when we get a notification of group participants being added/removed
Merge pull request #584 from TitanNano/hide-chats

Hide conversations
fix for #534

This dispateches a event when the app is ready. So we can now wait until we register the mesage handler.
Merge pull request #585 from TitanNano/dev

fix for #534