Make unit deployment aware of deploy state

[FlyingWombat]

Deploying all units in a selection doesn't work right.
The current behavior is: for each unit in selection, toggle deploy state.

For example: if you have 3 GI, 2 deployed 1 undeployed, in the selection, and then press Deploy --> the result will be 1 deployed and 2 undeployed, instead of 3 deployed. This is a problem because the player can't deploy an entire selection of units.

The original RA2 behavior was: if any in selection is undeployed, deploy all; else undeploy all.