don't assume that filesys starts at / in Pod-Html

don't assume that filesys starts at / in Pod-Html

The test expectations for the --htmlroot feature wanted to look for
an absolute path, so it concatenated / with the relative-to-root path.

That failed on Win32, where the cwd was C:\etc

I added a new token to the test-expectations-munger for the absolute
cwd.  I'm not 100% sure about the features' behavior, but the tests
are now less platform-specific.  I look forward to input on whether
the code is doing the right thing now...