Usage of Key Names instead of Key Codes in config.

Enabled usage of Key Names instead of key codes in configuration file.
This required the external
keysym(`https://github.com/substack/node-keysym`) library. The Key Names
specification can be found at:
`http://www.cl.cam.ac.uk/~mgk25/ucs/keysyms.txt`.  Symbols are not
detected, they are actual Key Names. As an example: a semicolon should
be specified as `semicolon` and not as `;`.

Signed-off-by: Martin Jorn Rogalla <martin@martinrogalla.com>
Added additional dependency to README.md

Signed-off-by: Martin Jorn Rogalla <martin@martinrogalla.com>
Added keysym dependency to `package.json`.

Signed-off-by: Martin Jorn Rogalla <martin@martinrogalla.com>
Merge pull request #30 from AirWM/keyNames

Enabled usage of Key Names instead of Key Codes in configuration file.