replace enableForegroundNdefPush with setNdefPushMessage

enableForegroundNdefPush is deprecated but doesn't seem to work with ICS devices. Replace with setNdefPushMessage, which works, but requires user intervention before sending the message.
NDEF_PUSH_DISABLED
Merge pull request #50 from don/p2p-android-14

update peer-to-peer to work with android 4.0