Alg3 working.

 * Fix off-by-one error looping over m
 * Avoid recalculating chunk_size when receiving vector
 * Add local dev rules to Makefile
 * Avoid float operations for partner/receiver/sender calculations
Implement sum using MPI_reduce
Add serial implementations of naive and blocked multiplication
Remove hello world example
Remove hello world from Makefile, matrix multiplication uses double instead of int