Add Greedy Algorithms

[abhisheknalla]

Sir, there seems to be only one greedy algorithm implemented. I will add the following algorithms:
Kruskal Mst
Prim Mst
activitySelection
huffmanCoding
jobSequencing
travellingSalesman

I will add commented code along with Readme files

[prateekiiest]

I guess, Kruskal , Prim's are already there