README file are now in marked down format

Fix file names for README files

Author: wkliao

wiki/Documentation.html

@@ -33,15 +33,15 @@
 <h2>Build PnetCDF Library</h2>
 <ul><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/INSTALL">INSTALL</a> contains detailed instructions and required software for building PnetCDF library.
 </li><li>Several README files contain build recipes for specific platforms, including
-<ul><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.CRAY">README.CRAY</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.Fujitsu">README.Fujitsu</a>
+<ul><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.CRAY.md">README.CRAY</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.Fujitsu.md">README.Fujitsu</a>
 </li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.IBM">README.IBM</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.INTEL">README.INTEL</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.K-Computer">README.K-Computer</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.LINUX">README.LINUX</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.SGI">README.SGI</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.SX">README.SX</a>
-</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.Ubuntu">README.Ubuntu</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.INTEL.md">README.INTEL</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.K-Computer.md">README.K-Computer</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.LINUX.md">README.LINUX</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.SGI.md">README.SGI</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.SX.md">README.SX</a>
+</li><li><a href="https://github.com/Parallel-NetCDF/PnetCDF/blob/master/doc/README.Ubuntu.md">README.Ubuntu</a>
 </li></ul></li></ul>
 
 <h2>PnetCDF API Reference</h2>