lib: separately define fragments and their titles

 this allows setting fragments inside onCreate
 which allows using of Context while populating fragments

 older implementation would not allow using Activity's context
 to help create fragments
lib: add class to set and get contact details
lib: use Contacts object instead of hashmap

  hashmap can use only 2-value pair
  Contacts class can add support for multiple
lib: fix using of contact objects
app: start using Contacts data object