Improved queries counting

[Xymanek]

I've added a new way of counting queries. The differences are as follows

• $this->num_queries now holds amount of queries that were run since object's creation
• $this->conn_queries now holds amount of queries that were run since the last time object connected to DB (it is reset every time the $this->disconnect() and $this->connect() functions are called)
• A new function $this->count() has been added with 2 arguments:
  1. Controls whether the function should return total number of queries (default) or only since last connect
  2. Set to true to increase the query count (internal usage)

This change also fixes #72

P.S. While making changes I've found that not every class implements $this->disconnect(). Is this supposed to be so?

[fawaf]

good question. @jv2222 could you answer that?

[fawaf]

i would think that $this->disconnect() not implemented everywhere is an oversight, but i want to confirm with @jv2222 since he is the original author of the code.

also, cc @ozh

[jv2222]

Thanks All.