Add ARRAY-BOX

[stylewarning]

Add array-box which allows you to specify the type of alignment for each row and column. This could be used to implement matrix-box (issue #1), row-box/column-box with options (issue #2, #3), and latex-align-box.

[matt-y]

Hi @stylewarning . I'd like to help out with this.

[notmgsk]

@matt-y #12