WL#256: SHOW FUNCTIONS

Make SHOW FUNCTIONS (or SHOW UDF) display a list of all available 
User-Defined Functions in one column and if loaded or not in another 
column.
 
 
[PeterG comment] Like worklog item #588, this is a request for a new type of 
SHOW. I believe that all SHOW enhancements will be redundant once we have a 
good implementation of INFORMATION_SCHEMA (currently worklog item #173 but 
needs editing). 

This is made obsolete by WL#2950