Add ABLConditions class

[mostaphaRoudsari]

This object should be initiated from wind tunnel information

Uref                 2.8; // wind velocity
Zref                 10;    // reference z value
z0                   uniform 1; // roughness
flowDir              (0 1 0); // velocity vector
zDir                 (0 0 1); // z direction (0 0 1) always for our cases
zGround              uniform 0; //min z value of the bounding box