The short versions:
OPR stands for "Offensive Power Rating," and is primarily used to determine the contributing power a robot contributes to an alliance. The higher the OPR, the more scoring power a robot will have.
DPR stands for "Defensive Power Rating," and is used to determine how defensive a robot is. It works the
same opposite as OPR, the
higher lower the better.
CCWM is "Calculated Contribution to Winning Margin," and is used to describe how much of a positive impact a robot brings to an alliance. Higher CCWM indicates more good things will happen to the alliance during a match such as drawing the defense away, providing secondary scoring, and so on.
You can check Ed Law's presentation on OPR and CCWM here. I do have a file by Ed Law also on DPR if you want to look at that too. I don't remember how I managed to find this, but I will PM you the file if you would like to see it.