Attempts to fix a problem in the reading of the configuration of the encodings (in the Media configuration form) from configuration files created by earlier versions of SIP Communicator.
When distinguishing MediaFormats, takes into account their clock rate as well because the encoding String isn't unique.
Fixes an issue reported by Lubomir Marinov on dev 06/15 (Add contact and call buttons are not disappearing, when the search field is cleared). The problem seems to appear when the contact list view is empty (no contacts or if showing only online contacts and no account is online).
Removed unused field.