An Implementation of SHA in APL

I supplant my 2019-12-06 and 2020-02-20 APL SHA articles with this, implementing the entirety of the
SHA-1 and the SHA-2 family; variations on SHA-512 are trivial to construct manually where necessary.

I will improve this program and adjust its interface at my leisure.  Do not expect to use it without
observing modifications.  I may provide an overarching SHA function or a nice SHA-512/NNN interface.

Read the previous two articles for more in-depth documentation which I don't currently provide here.
.