Fixing encoding of decimals ending in .0 or 0.0
Version bump to v2.0.2
Make sure statements that are added to a batch are prepared

When executing a prepared statement it will make sure that it's prepared on the connection before sending the request, but when a prepared statement is added to a batch it doesn't do this check, instead it raises a NotPreparedError. With this patch the batch will prepare any unprepared statements before sending the batch request.

This fixes #117
Fix Batch#add with synchronous prepared statements

The previous commit fixed a bug, but introduced another: if the statement was a synchronous one it failed...
Fix a small syntax issue in the Batch docs
Fixing varint and decimal encoding/decoding
Version bump to v2.0.3
Add jruby-head to the Travis build matrix
Fix a bug in the frame decoding

The size of the remaining buffer needs to be decremented by the size of the trace ID. This is basically only relevant for raw row responses since they are the only thing that care about the size of the frame, everything else reads the structure and then discard the remaining bytes (and that part works fine as far as I can tell).