(top-level): Move (provide 'cua-base) to end.

(top-level): Move (provide 'cua-base) to end.
No longer provide 'cua.  Don't require cua-rect, cua-gmrk when compiling.
(cua-set-rectangle-mark): Add doc string to autoload.
(cua--rectangle, cua--last-killed-rectangle)
(cua--global-mark-active): Always define for compiler.
(cua-copy-rectangle, cua-cut-rectangle, cua--rectangle-left)
(cua--delete-rectangle, cua--insert-rectangle)
(cua--rectangle-corner, cua--rectangle-assert)
(cua--insert-at-global-mark, cua--global-mark-post-command):
Declare as functions.