* Added parameter `array-strictness', default #t
* Added `array-default-strict!' and `array-default-strict', which act
like the functions without "default" in the name when
`array-strictness' is #t; otherwise they do nothing
* Lots of small changes to existing array functions, mostly to ensure
computations are done using nonstrict arrays, but return values are
strict when `array-strictness' is #t
* Added strictness tests
* Added tests to ensure untyped code can use `math/array'
* Rewrote `array-map' exported to untyped code using untyped Racket
* Rearranged a lot of `math/array' documentation
