Apple has posted its tech specs for the third-generation iPad, revealing a number of unspoken features and limitations. The page reveals that the new iPad boasts Bluetooth 4.0 support, as well as a considerably larger 42.5-watt-hour battery. The previous limitation of 720p AirPlay Mirroring remains—even when using the new device with the upgraded third-generation Apple TV announced today—but the new iPad is capable of streaming AirPlay…