Zero-K v0.8.9 released

Several significant changes, particularly to artillery comms and chicken mode. Take note!

* Nanospray converted to a nanolaser at lower graphical settings; works with Lua shaders off (e.g. minimum settings)
Modules
* Reworked Plasma Artillery conversion:
* Basic version has medium damage and rate of fire, with some inaccuracy (particularly against moving targets).
* High Caliber Barrel makes it comparable to the old artillery module.
* Napalm Warhead sets targets on fire briefly, but does not create a fire cloud. To get the fire cloud effect, both High Caliber Barrel and Napalm Warhead are required.
* All combinations have a shorter base range than the old arty module.
* Companion Drone will not fly further than 450 m from the parent commander (half of previous range).
* Disruptor Beam no longer has a range advantage over Slowing Beam.
Gunships
* Rapier HP 1500 -> 1400 * Brawler HP 2400 -> 2800
* Banshee can fire 60° off-axis (from 45°)
Chicken
* Overhauled the system for greater transparency. A single value, the player aggression rating (aggro), controls chicken responses to tech.
* Positive aggression ratings cause the chickens to spam more and produce defenses.
* Negative aggression ratings cause the chickens to tech faster and produce more Toads. At sufficiently low values, the chickens can use special abilities to bypass defenses.
* Added a new flyer chicken, the Roc.
* Faraday delay between shots 2.4s -> 2.8s
* Defender damage 110 -> 105
* Crabe can cancel its curling before completion
* Fixed an occasional error with Stiletto attack runs
* Readded comm selection announcements
* Advanced camera disabled by default