Updated Electric Parts Expanded for v1.15.1.

Added an electric sensor relay part, which sends an on signal when powered.
Updated the models for the capacitor and compact relay parts.

Added a small thruster intended for ROVs.
Added a mini motor.

Added a small robotic hinge.
Added a servo which is similar to compact robotic hinge but has a larger range of motion.
Added a power socket.
Added a weight bolt, which is similar to a weight block, but does not have physics.
Added the 'EPE' tag to all items for easier searching.

Added a drone propeller.
Added a tiny electric motor intended for use with drones.
Reduced the flat solar panel weight to match its size.

Added a flat power pack.
Added a prefix to definitions and meshes to prevent conflicts with other mods.

Uploaded Electric Parts Expanded to the Workshop.