Some performance improvements

This is to separate possible performance improvements described in ODBC-313 from original core issue (redundant call of SQLPrimaryKeys by the code generated by Embarcadero, or does it make more sense to talk about Interbase).
In this way, this ticket is dedicated to following things
1) Suboptimal tx_isolation query
2) That INFORMATION_SCHEMA query should use '=' rather than 'LIKE' - those parameters of SQLPrimaryKeys may not be a pattern
3) Statement reset can be optimized. They are issued on cursor closing( SQLFreeStmt with SQL_CLOSE), and in most cases are not needed
4) Queries, issued by the connector should be assembled in batches, if possible. This is going mostly about configuring the session at connect time.
5) Use session tracking feature of servers. That makes item 1 less relevant, but not all servers out there support tracking.