Fixed fragment restoration issues

- Now properly restored, should not be re-created after restoration
- Tab should not be selected twice or more
Made NetworkMapFragment persistent even when selected tabs are changed

What I hav learned:

- All fragments should be managed by FragmentManager. Should not make any fields of Fragments or lifecycle will be somewhat broken.
- Use add and hide rather than replace to keep fragments alive while another tabs are selected, but this may consume too many memory. Didn't tested with multiple fragment container activity layout so I don't know it works or not.
- Use Bundle(savedInstanceState) as far as possible.