Remove frame operations

Emacs 24.4 has built-in `toggle-frame-maximized' and
`toggle-frame-fullscreen'.
Fix hunspell English dictionary could not be found

(ispell-find-hunspell-dictionaries) could not parse the output of
`hunspell -D' for en_US dictionary when the environment variables LANG
or LC_ALL is not been set in Emacs. It could only find dictionary whose
name is "default". Either rename dictionary files to "default", or set
LANG or LC_ALL to en_US could resolve this issue.

If hunspell is not installed, fall back to ispell.
Switch between two recently used buffers C-x C-b

Original (ibuffer) is rarely used.
Auto save buffer to the file for every 5 seconds
Refine whitespace mode settings

Use (delete-trailing-whitespace) instead (whitespace-cleanup) to remove
trailing whitespaces.
Support kill buffer without asking by C-x C-k
Rebind (magit-status) to F4
Remove (revert-buffer) keybinding

(global-auto-revert-mode) has been enabled.
Adjust (smex) and desktop keybindings

(smex) is frequently used which deserves a special key. Bind (smex) to
F12, and rebind (desktop-save) to F9.
Enable (show-paren-mode) the right way

(show-paren-mode) is a global minor mode. It should be enabled only
once.
Refine `ggtags' settings

* Call (push-mark) before jumping.
* Use default ggtags keybindings.
Refine `elisp-slime-nav' settings

* Call (push-mark) before jumping.
Add package `mark-tools`

Use M-x list-marks to show the positions in `global-mark-ring'
Refine jedi settings

* Fix install information about external packages
* Move jedi settings to the top level
* Defer variable settings
Add instruction to build Emacs from Git
Fix #1: Do not show empty lines in whitespace-mode

It doesn't look good with auto-complete.