Add OpenLibm url - http://openlibm.org/

Author: ViralBShah

README.md

@@ -1,6 +1,6 @@
 ## OpenLibm
 
-OpenLibm is an effort to have a high quality, portable, standalone
+[OpenLibm](http://www.openlibm.org) is an effort to have a high quality, portable, standalone
 C mathematical library ([`libm`](http://en.wikipedia.org/wiki/libm)).
 It can be used standalone in applications and programming language
 implementations.