Replace set command with set-option command

Alias set is useful for interactive work. In config file it is much
better to use long explicit command names.
Change comments to imperative form

Comments in imperative form look better while reading the config.
Add aggressive-resize option
Separate config into key bindings and options sections
Clarify comments for key bindings
Replace unbind and bind commands with long versions

Long verbose commands names are better in config files.
Update Vim plugin YouCompleteMe to latest version

Latest version is e0e9fb9751b9fe1d254edbaa8ebbc1867b3465d3.
Set git to ignore changes in YouCompleMe submodule
Add textwidth option for reStructuredText filetype

reStructuredText filetype options supplied with Vim does not set text
width. Therefore, I set it up by myself to by 79 characters.
Update Vim plugin airline
[vim] Add spell file with suggestions for Russian
[vim] Add textwidth=79 option for python

This option conforms with PEP8 Style Guide for Python.
[zsh] Add aliases for cd ../../../ and cd ../../../../

Aliases '..' for 'cd ../' and '...' for 'cd ../../' already exists in
oh-my-zsh. As I use go to three and four levels up often, then I
decided to add aliases for this.
[tmux] Add comments symbols to section names

Without comments symbols there was a syntax error.
[tmux] Add binding to create window for development
[tmux] Set up Emacs bindings in command line
[tmux] Refine comments in configuration file

Remove ending periods from existing comments. Also add comments for misc
settings.
[tmux] Comment out sourcing Tmuxline file
[tmux] Beautify status line