Add TpawClientFactory
Submitted by Marco Barisione
Link to original bug (#706892)
Description
Ideally we should add a TpawClientFactory class, derived from TpSimpleClientFactory, to set some default features we need in tp-aw (like TP_ACCOUNT_FEATURE_STORAGE, TP_ACCOUNT_FEATURE_CONNECTION, TP_CONNECTION_FEATURE_AVATAR_REQUIREMENTS and TP_CONNECTION_FEATURE_CONTACT_INFO).
Them we should get EmpathyClientFactory to derive from it.
At the moment things (mostly) work because Empathy uses EmpathyClientFactory and GOA just sets a bunch of features it needs.