Rjb fix master for modern ruby

Here are some fixes that at least make webby work (for some value of work that was good enough for me). I didn't bother to get the rspec tests to run since they seem based on an ancient version of rspec

This addresses issues #7 and #9

The meaningful fix is the change from import to app.add_import and making file paths get expanded to full paths by File.expand_path in lib/webby/apps/main.rb