Cleanup before media lib changes

Move module source code to new /source folder
Make /libraries folder to contain sitecore lib(s)
Add Sitecore kernel lib and update reference in RedirectModule.csproj
Update .gitignore folder to ignore appropriate files outside of root
folder
Redirect media library items correctly

When the item found is under the /stirecore/media library, return a
media url instead of a link url. This prevents the dreaded cannot load
layout page.