Information about blocked threads within the AbstractInstancePool implementation

Hi

this patch adds information about the amount of blocked threads within the AbstractInstancePool implementation. Two new attributes are added to the JMX Management Interface:

• Waiting - the amount of waiting threads for this pool
• MaxWaiting - maximum amount of waiting threads for this pool

These informations can be used to check the current pool size (if it should be adjusted) or only to see the current waiting threads for this pool.

Kristian