Fixed CLOB UTF8 bug where value would be truncated and padded with
null characters when multi-byte charset is set.

Implemented by getting the chunkSize of the CLOB, then reading
that many bytes at a time, rather than getting the number of characters
(clob.length()) and only reading the equivalent number of bytes (which
fails for multi-byte characters).
Merge pull request #63 from raztus/clobUtf8Bug

Fixed CLOB UTF8 bug where value would be truncated and padded with