v0.1.6

This is a maintenance release to fix CRAN test failures caused by changes in the rlang package.

• The (minimum) required rlang version has been increased to 0.3.1. This version fixed a bug which prevented certain operator "sections" from being expressed. A chain like `/`(2) %>>>% sin (halve and apply sine) now works as expected.

• Formals of primitive functions now agree with those of base::args() (#18, #24). This means you can use args() to determine the names of arguments when using partial(). Thus, partial(`/`, e2 = 3) is the same as partial(`/`, , 3) is the same as division-by-3. Moreover, %>>>% chains are verified against the argument names given by args(). Thus, `/`(e2 = 2) %>>>% sin is valid, but `/`(y = 2) %>>>% sin is invalid—`/`() viewed as a closure has no argument called y.

• Support for R 3.1 has been dropped.