WL#993: LOAD DATA INFILE and character sets

Extend LOAD DATA INFILE to support specifying character sets for the whole
file and for field level.

PeterG> this new task should (I believe) be associated with a SAP DB    
PeterG> task, since SAP DB Loader allows specification    
PeterG> of the file character set.    
    

peterg> LOAD DATA ... INTO table-name CHARACTER SET x ...


bar> Tobias proposes this syntax:
bar> LOAD DATA INFILE 'file' INTO TABLE t1 ... USING charset
bar> which looks nice.
bar> We can support it together with SAP style syntax.


Note: cancelling this task; the functionality exists 
using different syntax, per the MySQL Reference Manual,
which says (at http://dev.mysql.com/doc/refman/5.0/en/load-data.html):
"13.2.5. LOAD DATA INFILE Syntax
...
The character set indicated by the character_set_database system 
variable is used to interpret the information in the file. SET NAMES 
and the setting of character_set_client do not affect interpretation 
of input."
-- Trudy Pelzer, 2005-12-13