- bindparam() names are now repeatable! specify two

- bindparam() names are now repeatable!  specify two
distinct bindparam()s with the same name in a single statement,
and the key will be shared.  proper positional/named args translate
at compile time.  for the old behavior of "aliasing" bind parameters
with conflicting names, specify "unique=True" - this option is
still used internally for all the auto-genererated (value-based)
     bind parameters.