Detour crowd optmizations

Optimizing dtObstacleAvoidanceQuery. Multiple issues:

 1. processSample receives a minimal penalty variable (presumably from former samples). Once the computed penalty is higher - the function exits without analyzing othrt collisions.
   [Note: Internally we use the penalty to compute a threshold time which is compared to the minimal hit]

 2. To improve the "early out" strategy, I changed the order of the search pattern in the adaptive evaluation (not the pattern, just the order). 
     Old order (increasing angle):  0, α , 2α, 3α, 4α, ... (n-1)α, nα.
     New order: 0, α , nα, 2α, (n-1)α, 3α, (n-2)α, ... 
This way closer to dvel angles are search first and can reduce later computations through minenalty early out.

3. Changed  from computiong cos, sin (>100 clocks each) for every angle to simple rotation.

4. A bug fix I found along the way: when vmax == 0 there was a divide by zero issue.