Add greedy algorithm for remove blocks

For red player, since he could remove any blocks he wants, so the greedy
strategy is to make either torques as close to 0 as possible
For blue play, since he could only remove blue blocks, so the strategy
is to make two torques' abs values as close to each other as possible

Add a getWeight function to make getting weight easier
Add isBlue and isRed functions to check if the  block is blue or red