this also addresses #8 and #12

1. we see that exact error in issue Plugin load if next is not available #8 running tests if next isnt installed in the project. should i try to mock it? :/
2. seems we don't need hasFramework anymore with the next require try/catch. also when this is upgraded to a core plugin, won't the framework check be done outside of the plugin?
3. tried to mock fs in the standard way i mock the other dependencies and ran into a handful of issues. i now use the mock-fs package but calling mockFs broke the internals of hasFramework despite efforts to pass a correct config to mockFs that would appease hasFramework ☹️