Reduce code duplication

Fix building of documentation and zip

Assorted changes

Better checks for arguments of partial LOB reading methods 

getBinaryStream() and getCharacterStream() with pos and length

Implement JdbcBlob.getBinaryStream() and JdbcClob.getCharacterStream() with pos and length arguments

Fix issue #754: Make NUMERIC type read as NUMERIC

Add DataUtils.parseChecksummedMap()

Do not copy result of DataUtils.parseMap() to a new maps

Fix ResultSet.getObject() for BigInteger and remove unneeded check