Connect once to APNS and send all pushmessages over that connection

- Added some methods to manage the streams
- Supports switching from and to sandbox between messages (not of much use now, but it's future proof)
- Reconnects when connection is lost
- No changes in the interface
- Major performance win!
Handle incorrect/corrupt pushmessages

- Implemented the new APNS binary interface, so we know what message triggered the error and what messages to retry
- Resend if we detect that the pushmessage didn't get through
Removed STREAM_CLIENT_PERSISTENT

We should not reuse/share the connection over multiple processes. Because Apple will return IDs of pushmessages that are send by another object.
Fixed undefined $length in writeApnStream()
Merge pull request #14 from wrep/feature/ios-bulk-send

Connect once to APNS and send all pushmessages over that connection
Added 'use' statements into README (closes #16)
fixed README formatting
Add validation pem file and handlers
Add functionality to iOSMessage
Fix logic error in iOSMessage construct
Add JSON_UNESCAPED_UNICODE option to configuration
Merge pull request #17 from ZhukV/master

Added validation in compiler pass and extension