kai'ei NUKEI experimental cmavo

abstractor: x1 (x2, ...) are such that they satisfy [bridi], using bo'a/bo'e/etc for variables

kai'ei is to kai'u what ka'ei is to ka. Uses bo'a/bo'e/bo'i/bo'o/bo'u (bo'ai for more variables) instead of ce'u (which may still be used for "next place").