add vmd 1.9.3 package

NB just releasing the nocuda version for now, but chosing a name that means we can also add the cuda version if it is useful.

packages/vmd_nocuda.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<packages:packages xmlns:packages="http://www.wpkg.org/packages">
+  <package id="vmd_nocuda" name="VMD (no cuda)" revision="%version%.1" priority="0" reboot="false">
+
+    <variable name="version" value="1.9.3" />
+    <variable name="fileversion" value="193" />
+
+    <check type="uninstall" condition="exists" path="VMD %version%" />
+
+    <install cmd='msiexec /qn /i "%WPKGSOFTWARE%\vmd\vmd%fileversion%win32nocuda.msi"' />
+
+    <upgrade include='remove' />
+    <upgrade include='install' />
+
+    <remove cmd='msiexec /qn /x {B47E68B9-DC9D-4CA4-A1D1-D973AA758CF3}' />
+
+  </package>
+</packages:packages>