Changes to pounce detection & the pouncing process.

[dGr8LookinSparky]

Note: This issue requires #140 to be completed first

• Remove angle of impact as a factor in pounce damage.
• Remove air acceleration from the basic goon and adv goon.
• Move pounce detection to its own function in bg_pmove.c, separate from client impacts, making use of the bgame area entities function. Apply knockback to the impacted targets in this function (and apply no knockback to the damage function), apply a velocity vector to the velocity of the pouncer normal to the point of impact proportional to the damage inflicted.
• Implement an initial transitional state of the pounce where the charge is gradually reduced and added to a transition pounce velocity variable , and for ground pouncers an area entities box is extended in the direction of the pounce during this transition,any impacted entities have knockback and damage applied from the transition pounce velocity variable as if it was the ground pouncer's velocity, and subtract from that variable any opposite impact velocities. Once the transition is complete, have whatever remains from the pounce magnitude function applies to the velocity of the pouncers, allowing the pouncer to leave the ground. Apply the pouncer's air control to turning while this transition takes place. For air pouncers (like the spitfire) this transition state is simply an acceleration period.
• Have the damage from chomp reduced for tragets with high relative velocities, proportional to the relative speed.

[redrumrobot]

If not having any air control doesn't feel good - then goon should probably lose some pounce-power based on how much they deviate from their unaltered trajectory