Fully implement Shockwave

[EricStein]

Shockwave class acts as an explosive force.

Properties:

* velocity

the speed at which the wave propagates in the medium

* energy

the total amount of energy the field is capable of exerting on other objects (in most situations, most of this will go to waste)

* radius

the maximum effective radius of the shockwave

* length

the thickness of the wave as it propagates