properly trim tags when adding a delimited list

[adamgruber]

Problem
Individual tags are not trimmed as expected when adding a delimited list.

Example

var instance = new Taggle('example');
var tagsToAdd = 'one, two, three, four';
instance.add(tagsToAdd);

instance.getTagValues(); // ['one', ' two', ' three', ' four']

// Expected tags to be trimmed => ['one', 'two', 'three', 'four']

Solution
Trim tags after splitting on delimiter if trimTags option is true.

[coveralls]

Coverage increased (+0.04%) to 90.084% when pulling 3eb976b on adamgruber:trim-tags into f84dcba on okcoker:master.

[okcoker]

Thanks @adamgruber 🔥