Divided saveExpenseActivity, provided up buttons

Decided to divide the SaveExpenseActivity into CreateExpenseActivity and
EditExpenseActivity as I encountered problems with up navigation that
might confuse the users, also this solves the problem of messing up the
code logic with ACTIVITY_COMING_FROM keys. Now this is not necessary.
Also did some minor changes with the structure of the packages and
moved all of the alert dialogs to the progress fragment

- Moved all of the prompts from previous Main activity to progress
  fragment.
- Created a separate fragment package.
- Separated the SaveExpenseActivity into CreateExpenseActivity and
  EditExpenseActivity
- set the rest of the parent Activities and back navigation in the
  Manifest.
- implemented the onResume() callback in ShowExpenseActivity