trim whitespace

I kept getting exceptions thrown from the AIAssertV because customClickURLString was producing a nil customClickURL.  Took a look at the data and saw this: 

@" https://control.kochava.com/v1/cpi/click?campaign_id=komarvelwarofheroesiosngmoco35550ef979d142f4cd73e57cc80f4&network_id=190&device_hash_method=MD5&device_id=838953fe3eca71df0916d297fc1c4f3f&device_id_is_hashed=true&device_id_type=idfa&mac_md5=&openudid_md5=&site_id=1&pbr=1"

Notice the leading whitespace, which is not a valid URL.  added a trim method to that field.  Since its possible send down faulty server data for this field its likely to be possible to send down faulty data for all the fields and a better fix might be to add validation / trimming to every field in the dictionary.