Make the Mantis slower but give its primary attack a slowing and stamina draining effect.

Mantis speed: 1.3 → 1.25, Slow time: 1s, Slow modifier: 0.75, Total stamina
lost while slowed: 20%.
Don't penalize Mantis pounce when moving up a slope.
Make AI use the Mantis pounce.
Move stamina usage, restoration and loss into a single synchronized function.
Make Mantis slow actually work.
Fix a potential loop.
Remove unused variables in ClientTimerActions.
Set both team's build delay to 60% of build time.