Pull request to merge source code of heat_stencil and matmul_optimized

Hi,

We have added our source code for heat stencil and matmul described in our paper "Programming the Adapteva Epiphany 64-core Network-on-chip Coprocessor". Two folders have been added here, namely "heat_stencil" and "matmul_optimized".

Thanks,
Anish Varghese