Small MySQL Connection: MySQL database access wrapper

This class is a very simple wrapper to access to MySQL databases.

It can:

- Establish database connections
- Execute manipulation queries and return the number of affected table rows
- Execute an SQL SELECT queries and return the result set data in a bi-dimensional array
- Execute an SQL SELECT query and return a single value if the results just contain one row and one column
- Execute an SQL SELECT query just to count the number of result set rows
- Display the error message in the current script page when an error occurs