Added research tree functionality for the Harbinger variants.

Added the Harbinger Railgun in three variants:

Tri-Barrel Planetary Defense Turret
Single-Barrel Low-Mount Turret
Single-Barrel Static

Fixed Ramses Turret block mount points.

Re-worked Hydra Turret model & icon

Re-worked Hydra Missile Model & Icon

Re-worked Hydra targeting distance and damage values.