Create own module system

[marc1706]

Proposal:

While the phpBB module system that is currently used works it is far from being perfect for this MOD. Some parts are somewhat hackish, i.e. the add-on system and enabling/disabling modules. For a more efficient way of loading modules and in order to have a more user friendly module system the phpBB Statistics MOD should use it's own module system.

Possible issues:

• no compatibility with older versions
• if the above applies we'll need to move to 2.0.0