- merged "fasttypes" branch. this branch changes the signature

- merged "fasttypes" branch.  this branch changes the signature
of convert_bind_param() and convert_result_value() to callable-returning
bind_processor() and result_processor() methods.  if no callable is
returned, no pre/post processing function is called.
- hooks added throughout base/sql/defaults to optimize the calling
of bind param/result processors so that method call overhead is minimized.
special cases added for executemany() scenarios such that unneeded "last row id"
logic doesn't kick in, parameters aren't excessively traversed.
- new performance tests show a combined mass-insert/mass-select test as having 68%
fewer function calls than the same test run against 0.3.
- general performance improvement of result set iteration is around 10-20%.