Added support to unmarshall NDEF message during TechDiscovered notification.

Also refactored ContentHelper code so that responses in ContentHelper simply
relay the information to SystemApp. It is now the responsibility of
SystemApp(NfcManager) to convert raw payload to NDEF appropriate objects
Merge branch 'master' of ssh://github.com/svic/mozilla-central into master1

Conflicts:
	dom/system/gonk/NfcContentHelper.js
Fixed sessionID logic at the time of sending NFC XXX requests to nfcd

Also fixed some minor comments such as function names, NITS etc