Refine aethanyc-toggle-frame-maximized

`toggle-frame-maximized' is not available in Emacs 24.3.1.
Enable yasnippet only in python-mode

If yasnippet is useful in other major-mode, it can be enabled later.
Enable ido-ubiquitous

This issue is fixed.
https://github.com/DarwinAwardWinner/ido-ubiquitous/issues/24
Remove package `git-gutter-fringe'

It does not work well with ediff launched by magit.