[Java] Add tryClaim API to the RingBuffer

[vyazelenko]

With the new tryClaim API it is possible to implement zero-copy publication by writing directly to the underlying ring-buffer.

Implementation details:

• tryClaim - reserves space in the underlying buffer and writes a header with the given msgTypeId and a negative record length
• commit - flips the sign on the record length field
• abort - writes PADDING_MSG_TYPE_ID into the type field and flips the sign on the record length field

Example of API usage:

final RingBuffer ringBuffer = ...;

final int index = ringBuffer.tryClaim(msgTypeId, messageLength);
if (index >= 0)
{
    try
    {
         final AtomicBuffer buffer = ringBuffer.buffer();
         // Work with the buffer directly using the index
         ...
         ringBuffer.commit(index); // commit message
    }
    catch (final Throwable t)
    {
         ringBuffer.abort(index); // allow consumer to proceed
         ...
    }
}

Closes #197