win32: move default install path inside program files

All of the 'space in path' problems have been resolved, so
we can install Mercurial the Windows standard location.  The
{pf} InnoSetup variable is locale aware.

contrib/win32/ReadMe.html

@@ -33,7 +33,7 b''
       href="http://hgbook.red-bean.com/">Distributed revision control
       with Mercurial</a>.</p>
 
-    <p>By default, Mercurial installs to <tt>C:\Mercurial</tt>.  The
+    <p>By default, Mercurial installs to <tt>C:\Program Files\Mercurial</tt>.  The
       Mercurial command is called <tt>hg.exe</tt>.</p>
 
     <h1>Testing Mercurial after you've installed it</h1>

contrib/win32/mercurial.iss

@@ -15,7 +15,7 b' AppUpdatesURL=http://www.selenic.com/mer'
 AppID={{4B95A5F1-EF59-4B08-BED8-C891C46121B3}
 AppContact=[e-mail]
 OutputBaseFilename=Mercurial-snapshot
-DefaultDirName={sd}\Mercurial
+DefaultDirName={pf}\Mercurial
 SourceDir=C:\hg\hg-release
 VersionInfoDescription=Mercurial distributed SCM
 VersionInfoCopyright=Copyright 2005-2007 Matt Mackall and others