CC Mode: Do nothing in before/after-change-functions for text property changes
Fixes bug#20266.
lisp/progmodes/cc-mode.el (c-basic-common-init): Make
yank-handled-properties buffer local, and remove 'category from it.
(c-called-from-text-property-change-p): New function.
(c-before-change): Don't do anything if a call of the new function
returns non-nil.
(c-after-change): Don't do much if a call of the new function returns
non-nil.
(c-extend-after-change-region): Put changes to text property 'fontified
inside c-save-buffer-state.