Revert "Back end: Refactored threading."

This reverts commit 38c1d555175dd5a2a409ec348ee0a3dac5e53d49.
Revert "Refactored the Android application structure."

This reverts commit 68c60d0ce38244bda500bba459dc507e321faa63.
Revert "Revert "Refactored the Android application structure.""

This reverts commit 037b4f98ac4ef59e2af769533387de9009d75b36.
Revert "Revert "Back end: Refactored threading.""

This reverts commit a9b16c331090e04a1ffd658721965284cad9fb90.
Back end: Refactored threads. Still faulty.