Fixed RFC 4235 notifications compliance.

The RFC states that a NOTIFY sent after a SUBSCRIBE (initial
or refreshed) must contain a full state notification.
However, a NOTIFY sent after a PUBLISH must contain a partial state
indicating the specific state change.

Without this patch, OpenSIPS actually publishes a full state
notification in all cases (despite announcing a partial notification),
making the publish ordering fix patch useless.
Code beautification.

Use a 4-chars wide tab for indentation instead of spaces.
Merge pull request #62 from dsandras/ds-dialoginfo-notifications-fixes

Fixed RFC 4235 notifications compliance.
- when starting the FR timer, it should not override any previous setting of a FR or FR_INV timers.
  Solves Issue #25 (reported and troubleshooted by Mayama Takeshi) when a very fast 100 reply may stop retransmissions, but brake the updating of fr timer from FR to FR_INV state.
-  Gracefully detect if the uac_auth modules is available for usage in b2b_entities modules - do not through an error message but rather an info one, as find the uac_auth module is optional.
- fixed CANCEL matching in B2B
- backport from 5c9b24f
always free the DB result ( or else subsequent select queries will/might fail )
Fix PUA module so that it sends a final PUBLISH on expiration.

A final PUBLISH with expires=0 is now generated when a publication has
expired. This will trigger the transmission of a final state NOTIFY.