Adjustments to Style & Content

 Style changes
  - Site format has changed back to ~80 columns, certain rows have had line
    breaks removed.
  - Indentation has been adjusted globally to give additional space and
    consistency.
  - Configuring Tmux has been separated due to long lines causing the entire
    page to scroll horizontally and block text.
  - tmux.conf has been reorganized to better explain settings categorically to
    new users.

 Content Changes
  - Unmapping the prefix key contained erroneous data
  - Misc section and it's contained "bind r source.." setting are superfluous,
    as when this points to the next file to use in the configuration, not the
    current file. Since no additional configuration files have been used, it
    has been removed.
Correct Contributor's list & line spacing

- Contributor's list had an improper character which ruined the formatting.
- The Theme section was preceded by three line breaks rather than two.
Updates to tmux.conf

  Added reloading tmux configuration
Merge branch 'master' of github.com:adambard/learnxinyminutes-docs

Merge changes
Merge pull request #794 from wzsk/master

[tmux/en] Improve style & content