New models for cannon and short barrel cannon.

TY Lazermaniac
Engine buffs, Stubbyguns, updated cannon models

-Buffs to large B6, V8 and V12; small v12s and 13L v12 special  received
minor buff
-New multifuel v6 special
-Turbines now require fuel but have crazy output power
-Short barrel cannons added, these trade penetrative abilities and
accuracy for size and light weight
-37mm cannon added
-Fixed anims on lazermaniac's new cannon models
whoops

revision and changelog updated
Fixed something in cannon models
Note to self:

Make sure you check you don't get extra text on a ctrl-a ctrl-c.  Dammit
sexy undo!
Short-Barrel Cannon Adjustments

Gun weight decreased a bit to account for heavier shells. RoF changed
slightly.
Merge remote-tracking branch 'upstream/master'
Various fixes and balancing

--Cannon and short-barrel cannon models are now skinnier
--CoH sounds fixed
--Small v12 petrol/diesel and medium v8 diesel weight slightly increased
--Large CVT torque rating increased from 3400 to 6000
--37mm cannon name fixed
--37mm short-barrel cannon rof adjusted
Some new tank sounds

Engine and a few misc
Resampled new sounds to 44100 hz
Merge remote-tracking branch 'upstream/master'
Diesels more durable

Diesel engines have much more hp, and can take more damage before
performance degrades
Merge remote-tracking branch 'upstream/master'
New tracers, turbines use more fuel

--New tracers that are a bit brighter and much easier on older systems,
courtesy of Techa
--Turbine fuel consumption doubled
--Diesel fuel is no longer explosive
--Refuel sound is much quieter
Merge remote-tracking branch 'upstream/master'
Heat rebalance, misc fixes

HEAT rebalanced:
-HEAT HE reduced, 22% (down from 33%) of a HE shell of same caliber.
-HE effect is correctly sized
-penetrator loses less energy on initial penetration, but loses massive
amounts on successive penetrations. End effect is layered armor is much
more effective at stopping penetrator.
-penetrator deals 13.2x more damage to crates, roughly equal to an AP
shell of the same caliber as the HEAT shell.
-penetrator deals 6.6x more damage to engines and fuel tanks, roughly
half of an AP shell.
-penetrator damage to everything else is unchanged.

Diesel explosions can be triggered by HE or HEAT.
HE blast radius and blast energy is now correctly displayed on the tool
and overlays.
Merge remote-tracking branch 'upstream/master'
Large crate bonuses, ent loader

-Large volume crates (2x4x4+) have bonus ammo and confer a bonus to fire
rate or reload time.
-2x4x4 is +10% ammo, +2% fire rate / reload speed bonus
-4x8x8 is +50% ammo, +10% fire rate / reload speed bonus
-Guns without clips get a fire rate bonus, guns with clips have a reload
speed bonus instead
-Updated gun definitions so they are defined similarly to engines --
each gun class has its own file
Merge remote-tracking branch 'upstream/master'
Fixed client timeout and lag issues related to ACF not checking if a sound is valid before playing it repeatedly.