LiveDevMultiBrowser should properly search parent directories for an index.html

Presently, LiveDevMultiBrowser gets stuck in an infinite loop trying to step into parent directories to find an initial index.html if none is present in the current directory. Without the fix, the included test will loop forever.
@dsrw, there's a `FileUtils.getBaseName()` which should be used here instead of `FileUtils.getDirectoryPath()` -- it will do the job right.