TODO:

1) Write a proper test suite.

2) Make the file position / eof operations aware of the number of lines read
   from the database instead of following the chunks of data actually read.
   At the moment the position / eof does not follow the lines read with 
   READLINE ( <$handle> ) which is a BUG.

3) Implement buffering of the database reads, up to the specified block size.
   Currently when we do a read, we read those bytes directly from the database.
   We should do a read of $blocksize bytes but only return the requested number
   of bytes. This way we can make smaller reads look faster.