Adding missing dependecies for guard
Adding interface changes for commands
Changing command method documentation
Removing is_on? and is_off? from firmata commands

This two methods don't perform any action, they are query methods
for the status of the led, therefore shouldn't be considered
commands
Adding validation when sending only one param to commands

With this change, there will be a unified interface for
sending command params

Before you have to send: '"params":"first_param"'

Now you can send one or multiple params with an array

one param: '"params":["first_param"]'
multiple params: '"params":["first_param", "second_param"]'
Adding params to commands in Web API UI

An input text is added so commands can be called with params.

Right now, you can send params in plain text as if you were calling
a method normally

Example:

def brightness(level)

Command can be called by inserting in input text: 1 and pressing
brightness option in commands button.

If more than one param is sent then use commas to separate them: 1,"2"

This initial implementation is intented only to exercice API by knowing
how you call the commands, expecting a more robust solution later.
Merging master
moving params input to the right
Merge pull request #25 from hybridgroup/api-commands

Api commands in API web page
Merge changes from upstream