Update master

just updated the whole lot.

I don't think I've changed much in this version, but just in case....

tried adding a few comments and try to tidy it up

a few little edits to align label/input for bigger width viewports

added clear last button

edited CSS

added the JS funcionality for the clear last :)

Merge pull request #3 from peterbailey/master

Do not output px or % when value is zero - it is zero regardless of the unit

changed value to placeholder

added the box-sizing form / div

added styling for box-sizing css

added clear input function // added box sizing jquery

Merge pull request #2 from pmcelhaney/patch-1