config for ways to omit declarative shadow dom (lightMode)

[thescientist13]

Related Issue

resolves #18

Summary of Changes

1. Add config (lightMode) for omitting <template> tag for custom element renders

TODO

1. Safari seems to be missing styles for some elements
   Details

   
2. Add specs
3. Add documentation
4. Am I implementing / using includeShadowRoots correctly? I could read it two ways (might want to track as a new issue) - made a gist - verify / ensure proper serialization of shadow roots excluding closed shadow roots from getInnerHTML #16
   • literally does not render shadow roots at all
   • just doesn't render / return them in <template>
5. Not sure if there is value in having a way to opt-out at the top level for this, like if your page is a custom element?
   Perhaps you want your page as light DOM, but still keep the shadow DOM for all nested children? Might want to make an issue to track. - verify / ensure proper serialization of shadow roots excluding closed shadow roots from getInnerHTML #16