[New Feature] Miner Mining Animation

[snmiglight]

Description:

When a unit is moving, WalkRate is used to control the unit’s animation, when it is idle, IdleRate is used. Voxels with anims for mining ores can play their 'mining' animation by setting WalkRate= to a large value (like 1000) and IdleRate= to a small value (for example, 4).
This workaround is flawed though; as when the miner turns idle, the animation intended for mining will play. Having a true mining rate for harvesters would be desirable in this case.

Possible Implementation:

[TechnoType]
MineRate= (integer - number of frames)
If higher than 0, defines after how many frames the unit’s animation
is to be advanced to the next frame when the unit is gathering ore. Defaults to 0.