Rewrite NDEF parsing in Java, clean-up API.

o Lots of documentation fixes.
o Add NdefMessage(NdefRecord ... records) ctor
o Add NdefRecord.createMime()
o Add NdefRecord.createExternal()
o Add toString(), equals() and hashCode() implementations
o Deprecate NdefRecord(byte[]) and NdefRecord.toByteArray()
o Remove framework dependency on libnfc_ndef.so
o Remove NfcAdapter.getDefaultAdapter(), its been deprecated a while

next step:
o Attempt to move NdefMessage -> Intent conversion into NDEF, and
  make it CTS tested. This will ensure consistent NDEF -> Intent
  mapping across all Android devices.

Change-Id: Ifed4910caa9a1d6bad32dbf0a507ab22bca35e22