- Added an optional C extension to speed up the sql layer by

- Added an optional C extension to speed up the sql layer by
  reimplementing the highest impact functions.
  The actual speedups will depend heavily on your DBAPI and
  the mix of datatypes used in your tables, and can vary from
  a 50% improvement to more than 200%. It also provides a modest
  (~20%) indirect improvement to ORM speed for large queries.
  Note that it is *not* built/installed by default.
  See README for installation instructions.

- The most common result processors conversion function were
  moved to the new "processors" module.  Dialect authors are
  encouraged to use those functions whenever they correspond
  to their needs instead of implementing custom ones.