classpgDB: PostgreSQL database access wrapper

This class implements a wrapper to access PostgreSQL databases. It can:

- Establish database connections
- Execute SQL queries
- Fetch the name, size and type of query result columns
- Fetch whole result sets into arrays
- Display information about errors, query results and for debugging
- Get the number result set rows or affected rows by a query
- Get the last inserted identifier of row with a key generated from a sequence
- Execute a query and return the results in a single call
- Escape text field values
- Insert or update rows using data from arrays
- Locks / unlocks actions or table fields
- Helper functions to deal with various types of data going into query where clause

For documentation visit http://www.graphinet.sk/wiki/index.php/PgDB_-_Database_Access_Wraper_for_Postgres