Reconcile register overwrite confirmation and kbd macros

Reconcile register overwrite confirmation and kbd macros

Give full control over overwrite confirmation to callers of this
function.  Provide a helper function that such callers can use to
adhere to standard behavior, and in particular skip confirmation while
defining/executing keyboard macros.

* lisp/register.el (register-read-with-preview): Simplify.
(register-confirm-overwrite): New function.
(point-to-register, window-configuration-to-register)
(frame-configuration-to-register, number-to-register)
(copy-to-register, copy-rectangle-to-register)
* lisp/play/gametree.el (gametree-layout-to-register)
* lisp/kmacro.el (kmacro-to-register)
* lisp/frameset.el (frameset-to-register)
* lisp/cedet/semantic/senator.el (senator-copy-tag-to-register)
* lisp/calc/calc-yank.el (calc-copy-to-register): Use it.
* doc/emacs/regs.texi (Registers): Update.
* test/lisp/register-tests.el (register-test-bug27634): Adapt.