Towards final weeks

Just before second evaluations I pushed some code to my PR adding the color square drawing functionality. So this week was mostly spent in addressing the code reviews on the PR and refactoring accordingly.

Majorly I fixed up imshow function by removing some premptive calls to norm and cmap. It mostly involved refactoring the code which was directly using shape of image assuming a 2D array to make it take shape of bivariate data also.

Currently I am trying to debug some issue with pcolor and pcolormesh functions where it hits some strange dimensional unmatch error in some C++ code on passing in BivariateNorm as norm.