Update and rename learntmux.html.markdown to tmux.html.markdown

Fixed some spelling, grammar, and punctuation issues 

Line  48:  Added additional items to the list of keybinds for power users
Line 104: Created section on configuring ~/.tmux.conf & added additional comments
Line 203: Added section including external resources
Update tmux.html.markdown

Corrected page structure/style to conform to other tutorials
```
Line  18: Removed "tmux" as it has other purposes as well as quickly starting a blank session that will not be covered
Line  45: Added Meta/Alt explanation 
Line 126: Moved 'bind-key C-a send-prefix" to the group that requires it
Line 184: Added comment 
Line 186: Added comment pointing to resource required (if enabled)

- Removed 'set-option -g status-justify centre'

```
fix code block

example tmux.conf was not nested as I previously thought. I combined the blocks and fixed the issue
Edit tmux.conf

- Added additional content to terminal management
- Sectioned each category, and restructured how they were grouped
- Removed 'set -g mode-bg' as users can read the manual page if this becomes something they want to customize
Fix terminal commands

Header syntax has been corrected
Remove syntax highlighting

bash syntax highlighting created issues with an open " originating in Keybinds. I have disabled syntax highlighting so the display is consistent
Remove tmux.conf

The linked resources have a few examples for users to build their own, and example configurations can be shared as links. This makes including it not too vital at the moment.

- Removed a handful of terminal commands & keybinds from the list
- Trimmed some overly-verbose paragraphs
Add tmux.conf

Re-add example ~/.tmux.conf
Merge pull request #1 from kaernyk/patch-1

[tmux/en] tmux tutorial