Set the font only when it is available

Ignore the issue that font the cannot be set in emacs daemon since emacs
daemon is rarely used.
Tidy up aethanyc-ui.el
Disable git-gutter-fringe

Ediff is not working with git-gutter-fringe.
Refine prog-mode-hook and add `paredit-everywhere'
Refine emacs and lisp mode hooks