added human readable colour support

[ste2425]

This will allow the picker to be given a human readable colour. Such as Red or Green. It will then parse that into a RGB colour code ignoring the set colour format.

Only when the picker is interacted with will it then use the set format. This is existing behaviour however. If it is set for HEX but given an RGB it will render and not change the format to HEX until the picker is interacted with.

It leverages getComputedStyle so has no jQuery dependency and does a check to see if it is supported before trying to use it. If its not supported the colour won't be converted.

this is in relation to issue #116

[ste2425]

Dam I didn't commit the changes. This currently implements .startsWith() but it isn't fully cross browser. I modified it to use .indexOf() I don't know how I managed to forget to commit it. I sort it now.