eliminate -d .git check by hacking VERSION when needed
version.pm used here
remove use of try_load_class - use_module is more straightforward
sort the modules before checking; for predictable testing
save up all issues to prompt just once per phase
keep track of modules as we prompt for them, so we do not check them twice (saves HTTP hits, repeated questions)
now that we track duplicates at lookup time, we don't need to screen them out here
[Bootstrap::lib] will not work if the pluginbundle requires a specific version
this is not needed here
ignore remnants of Test::DZil
Dist-Zilla-Plugin-PromptIfStale-0.005

          - now only prompting once (per phase) for all discrepancies found
          - no longer prompting for the same module twice, if there are
            multiple instances of the plugin running