Create indexed TubeFiredN and sum TubeFired hardware variables for mi…

[CMDR-Vulkarius]

…ssile events

Facilitated by introducing a simple fire counter per-tube:

• Increments when a missile projectile is spawned
• Resets when Weapons starts loading (successfully) something else into the tube

The TubeFiredN variables give float versions of each tube counter.
The TubeFired variable gives a sum of all tube counters for convenient setup of one DMX light.
These provide rising edges for triggering hardware events.

Example of hardware.ini suggested usage:

[event]
trigger = >TubeFired
target = MissileLight
runtime = 0.2
value = 1.0