Added cancel-reload!

Enhanced version of jj_Weapon.

It has these improvements over the original one:

1. Support for multiple instances of the same weapon. In the original version it didn’t pick the right instance when shooting, so all bullets came from the same weapon.
2. It triggers the on created event after spawning bullets.
3. Added support to modify the stock size from event sheets.
4. It can save its state when required (implemented 'saveToJson' and 'loadFromJson' methods) this is very important to persist the state of the weapons.
5. The UID of the shooting weapon is now available on shoot event.
6. Setting the bullet instance is now optional. This allows jj_Weapon to be potentially used for melee attacks or as some kind of timer with cool features.
7. NEW Added 'Set bullet instance by name' action which allows to set the bullet instance passing the object type name.
8. NEW Added the getLastShootTime expression that tells the last time the weapon was shot in milliseconds.
9. NEW Added last shoot time condition which triggers when has passed the given time in milliseconds since shoot.
10. NEW Added Is reloading condition.
11. NEW Added cancel reload action.