Terminal component

Start with a Terminal component inspired by [jQueryTerminal](
http://terminal.jcubic.pl/).

Currently support interpreter as a function, with an example of a
JavaScript interpreter.
Greetings can be a function as well

`props.greetings` can be a function so that the user can perform
any server request to retrieve the message.

The command prompt will only show if the command was executed and
an output was set through `this.echo` or `this.error`.
Prevent backspace from making browser go back
Navigating the history of commands

Using up and down keys to navigate previously used commands.
Use `props.history` to decide to serve history navigation

If `props.history` is set to `false` (default is `true`), then up
and down arrow keys won't do anything.
Auto scroll to the bottom of the terminal
Add support for limiting the output lines

Document the components a little bit.