Config for ignoring undefined attributes

[johngeorgewright]

Hey there,

I've written a possible solution to task #95.

Now attributes can be ignored when they are undefined in 3 ways.

1. By setting the ignoreEmpty option to true:

   Plates.Map({
    create: true,
    ignoreEmpty: true
   });

2. By specifying a particular attribute:

   Plates.Map({
    create: true,
    ignoreEmpty: 'id'
   });

3. By selecting a few attributes with an array:

   Plates.Map({
    create: true,
    ignoreEmpty: ['id', 'data-toggle']
   });

[johngeorgewright]

Nearly 2 years old. Closing.