Moved general operations into a separate file.
Added AS-ARRAY.
Added matrix type.
Added square-matrix.
Added default method for as-array.
Made general functions generic.
Added line breaks.
Added &dims.
Reworked the general interface.

Now everything falls back to DIMS.
Added default fallback.
Added ELEMENT-TYPE.
Reordered export list.
Added make-array-like.
Removed matrix and square-matrix types, cleaned up general interface.
Made TRANSPOSE generic.
Added array-matrix.
Cosmetic fix (removed duplicate).
Removed tranpose.