PyDB2 - Python DB2 Interface And Tools

The attached patch adds a sort of basic typecasting to the parameter values
on the execute() procedure.

For example now a str('1') as a value for an INTEGER parameter works
without throwing an exception.

It also has a little hack to enable the use of a 'date' value for a
TIMESTAMP parameter (it just appends the needed 'time' string to make the
string 'YYYY-mm-dd HH:MM:SS.NNNNNN').

Also, there is a double free() (glibc detected) when a cursor is closed or
'= None'd so I removed the PyDel that seemed to be causing this error.

Compiles and works fine with DB2 Express-C and python2.5, and I've tested
it with a django backend I'm also developing.