Description:
------------
Although Windows support has greatly improved with 0.3, there are still some rough edges. Namely, svn_diff (and possibly other functions) have a hard time figuring out if a file is versioned or not if the slash immediately preceding the basename is not a forward slash.

Reproduce code:
---------------
<?php

// Assuming . and C:/Users/Edward/svn are valid working copies
svn_diff('file1.txt', 'C:/Users/Edward/svn\file1.txt');

// Alternative syntax, different error
svn_diff('file1.txt', 'C:/Users\Edward\svn\file1.txt');

Expected result:
----------------
(no output; diffs are successful)

Actual result:
--------------
200005 (Tried a versioning operation on an unversioned resource) 'C:\Users\Edwar
d\Webs\lab\svn\diff\tests\Polynomial.php' is not under version control
 in C:\Users\Edward\Webs\lab\svn\diff.php on line 5

155007 (Path is not a working copy directory) 'C:' is not a working copy
720003 (The system cannot find the path specified.  ) Can't open file 'C:\.svn\e
ntries': The system cannot find the path specified.
 in C:\Users\Edward\Webs\lab\svn\diff.php on line 5