Add InPar ISPC paper to the repo

Author: dbabokin

documentation.html

@@ -100,7 +100,7 @@ <h1>Documentation</h1>
         on github</a>.)</p>
 
         <p>A technical paper
-            on <tt>ispc</tt>, <a href="https://github.com/downloads/ispc/ispc/ispc_inpar_2012.pdf">ispc:
+            on <tt>ispc</tt>, <a href="papers/ispc_inpar_2012.pdf">ispc:
             A SPMD Compiler for High-Performance CPU Programming</a>, by
             Matt Pharr and William R. Mark, has been accepted to
             the <a href="https://ieeexplore.ieee.org/xpl/conhome/6330715/proceeding">InPar 2012</a>