Issue #2318503 by slashrsm: Define basic interfaces.
Issue #2318503 by slashrsm: Fix typos.
Issue #2318927 by slashrsm: Remove legacy code.
Merge pull request #11 from slashrsm/2318927

Remove legacy code
Merge branch '8.x-1.x' into 2318503
Issue #2318503 by slashrsm: Extend FormInterface.
by slashrsm: Try to fix travis builds based on suggestion by @berdir.
Merge pull request #13 from slashrsm/travis_fix

by slashrsm: Try to fix travis builds based on suggestion by @berdir.
Merge branch '8.x-1.x' into 2318503
Issue #2318503 by slashrsm: Add empty functions to prevent fatals.
Merge pull request #9 from slashrsm/2318503

Define basic functions on interfaces