Please add abstract-arrays

[digikar99]

Please retrieve using the tags: https://github.com/digikar99/abstract-arrays

This library provides an abstract-array class and an abstract-array-class metaclass, which can then be used for creating concrete arrays like dense-arrays or sparse-arrays (yet to be done)! It also provides type specifiers for the specification of element-type and rank (and dimensions if you are using extensible-compound-types, albeit using satisfies type hackery.

[quicklisp]

Failure log here: http://report.quicklisp.org/2022-06-09/failure-report/abstract-arrays.html

[digikar99]

Added the description and made a small fix; could you please check if the new version v0.1.1 builds correctly?