This is a Docs repo, not Koding Support

Made a Readme change to point out that this is a repo and issue tracker
for documentation, not Koding Support/etc.

closes #123
Added Note for Non-Default Key

A note to the 4th instruction-step of the SSH guide, allowing for
non-default keys.

related #120
Fixed some grammar
Merge pull request #138 from leeolayvar/tmux

Tmux Guide
Merge pull request #137 from Joshua-Anderson/master

Fixed some grammar
Merge pull request #131 from leeolayvar/not-issue-tracker

This is a Docs repo, not Koding Support
Merge pull request #132 from leeolayvar/non-default-key

Added Note for Non-Default Key
Typo Correction