[x] Add coverage, whitespace, prettier, eslint and lint-staged
[x] Add .npmignore
[x] Update eslint settings
[x] Change option handling, simplify so that options don't have to be renamed
[x] Incorporate updates from in-place and review changes
[ ] Update readme and changelog
[ ] Recommend metalsmith-in-place in combination with templating languages that natively support template inheritance, explain why and what the function of layouts is
[ ] Incorporate changes from metalsmith-in-place readme
Closes #122