Potential fix for codesigning problems on OSX Mavericks

Would the changes in this pull request be considered for inclusion in PyInstaller? It changes the bootloader to look in Contents/Resources for files instead of Contents/MacOS.

The following thread talks about a problem with codesigning on the Mac:
    https://groups.google.com/forum/#!topic/PyInstaller/Rp6UUSJ7dP4

One problem that can occur with codesigning a PyInstaller package on OSX is if there are folders in the package like "Contents/MacOSX/sitepackages/gst-0.1". The codesigner thinks things in the Contents/MacOSX folder that end with a digit is a framework or versioned bundle and then stops saying: "object file format unrecognized, invalid, or unsuitable" Moving such a file to the Contents/Resources folder will make codesigner happy.

This pull request is some of the work needed to make this change. Before I work on it more though, I'm wondering if the PyInstaller folks would consider using these changes. If not, I won't work on it further.

-Winston