Readme was added

README.md

 CodeVault: Sparse Linear Algebra
 ================
+# Overview
+In this Sparse Linear Algebra folder, there are sample codes for beginners, as well as advanced codes including important computational kernels.
 
+# Contributors & Maintainers
+- Cevdet Aykanat (aykanat@cs.bilkent.edu.tr) 
+- Kadir Akbudak (kadir.cs@gmail.com) 
+- Reha Oguz Selvitopi(reha@cs.bilkent.edu.tr) 
+
+# Contents
+- spgemm: Multiplication of two sparse matrices.
+  - mkl_shmem: Using MKL's routine mkl_dcsrmultcsr() on a multicore processor
+  - mkl_xphi: Using MKL's routine mkl_dcsrmultcsr() via offloading to a Xeon Phi coprocessor