client will now substitute spaces for NULs, so that the grid isn't messed up
due to silently consumed NULs and that the full field is shown.


client/mysql.cc:
  For non-numbers, print each character at a time, instead of using the 
  fprintf() facility, which interprets an array of chars as a C string, which 
  is necessarily NUL terminated.  We mustn't terminate on NULs, and since we 
  know the length of the data, we needn't.
mysql-test/r/mysql.result:
  Add a test.
mysql-test/t/mysql.test:
  Add a test.