Fix #570: No newline after inline require

[jfmengels]

Breaking change - newline-after-import: Do not require empty line after inline require (fixes #570).

cc @singles @sindresorhus

I made two commits:

• One applying the change and making the new tests pass
• One simplifying the implementation by removing the whole usage of scopes (redundant with the level system I picked from the order rule, and a bit more complex IMO)

[jfmengels]

Rebased due to the merge of the v2 branch.

[coveralls]

Coverage decreased (-0.2%) to 97.61% when pulling 821a02d on newline-after-import-require into e3c41ca on master.

[coveralls]

Coverage decreased (-0.2%) to 97.61% when pulling b85b965 on newline-after-import-require into e3c41ca on master.

[coveralls]

Coverage decreased (-0.2%) to 97.61% when pulling b85b965 on newline-after-import-require into e3c41ca on master.

[benmosher]