docs: Remove data-setup property to prevent double initialization (#70)

[izkmdz]

Using the data-setup attribute in the video component will automatically initialize the player with the options provided. However, if the player is also initialized in our code using the videojs('my-player') function, this can sometimes cause the issue described in #70, where the quality selector is unable to change sources.

These changes remove the data-setup attribute from the documentation and demo to prevent this from occuring.

[coveralls]

Coverage remained the same at 0.0% when pulling 613e3116181a4e29ba51ad87351a57bd932ff858 on izkmdz:ismendoza/remove-data-setup into 8b1a0820615ad3f964b10bd939311c5abf302273 on silvermine:master.