Plan is to move our ConnectionX classess to the protocol package one by one. Each move should be more than a simple copy paste. It should be preceeded by cleanups and the like.

 * Make it testable and write a very basic test for the presenceCallback
 * Use Extract Method to make the code more readable and to increase reusability
 * Start to decouple ConnectionCaps from the other Connection classes/handlers

blacklist jingle in caps. TYhis mean that if clientr don't support caps, we assume it doesn't support jingle

Thanks Asterix for the initial version of this patch!

Public interfaces stay the same.

This prevents our caps cache from getting filled with invalid caps values. Furtheremore, NullClientCaps has been saveguarded so that it won't fail for people with already tainted caches.

Now we do:

contact.supports(feauture) instead of gajim.capscache.is_supported(contact, feature)

 * Rename EntityCapabilities to ClientCaps as this seems more intense giving.
 * Add ability to blacklist features where we cannot savely assume that a client, which did not advertise caps, supports them

Usage:

	if contact.supports(NS_E2E):
		....

Implement and test a supports_feature() method to directly test for supported featues on EntityCapabilites

 * remove js from some headers
 * set coding:utf-8 to allow real names in headers

 * Remove some licencing problems
 * To do: same for images
 * See #4200