Simplified basic ODBC_SQL call to take bindlist, sql query, and return result set.
Simplified bind variable passing to ODBC (more done in XSB)
Eliminated special handling of negative cursor numbers and first stmt numbers
by adding special calls for those special cases.
Changed cursor handling from a fixed array to an extensible list.
Modified bindlist handling in C to pass pointer to strings, without making a copy.
Move unification of returned strings to C side, to avoid internning atoms unnecessarily.
Changed the way types are supported (minor)
