Added support for backtick'd expressions under windows (e.g. `wx-config --libs`)
How does this works exactly? Is some external program required (I have MSYS) or it works out of box?
Everything works out of the box
The only note is that for non-NT windows (95,98,etc) you have to use the extension of the filename too, e.g. `wx-config.bat --libs`.
And, ofcourse, you have to create 'wx-config.bat' (or whatever else) yourself