Ability to skip the representation of dataset values equaling to 0

This ability can be handy to address the following use case: you want to represent data as a pie chart with custom colors passed as options. However, one or several of the computed values happens to be empty, and you don't want it to show up as empty sectors on the generated pie. But it's tricky to know in advance which indices will have a 0 value, and how the color array should hence be updated. An option would be to let the datasets contain 0 values, and to update the color array in JavaScript when some 0 values are encountered, when a dedicated option is activated.