Slim custom.el into personal.el; suppress warnings

Move most of custom.el into personal.el, with the exception of
custom-face-settings.  Now, customized variables will be quite obvious,
since they'll appear in a changed custom.el all by themselves, for
consideration for inclusion in actual personal settings in the
personal.el file.

Insert code in preload.el to suppress many compiler warnings relating to
free variable references and advice hooks redefining functions.