Settings screen v1.2
activity_main_actions.xml changed to question_fragment_settings.xml; 
added book_fragment_settings.xml; 
settings screen content change according to current screen not yet done.
#58 (strings.xml) updated, #11 (download page) started (missing listeners). Commented out backend from activity for testing purposes.
#11 (download page frontEnd) done, #12 (learnPage frontEnd) done with
correct swipe actions and long press shows questions. Some additions for
demo day too.
#51 #50 #22 #18 #17 #16 #15
Backend: Fixed bug: The application downloaded only one chapter (multiple times).
Fixed uppercase letters on book addition crashing the app. Removed some debug log calls.
Started with action bar. Changed question and add-book (WIP) screen
layout. Added animated transition for fragments (WIP, missing question
animation).
Back end: Started book update and delete functionality refactoring. #72, #75.
Removed the "Last chapter" field from the Books table.
Back end: Corrected the capitalization of book titles. Fixes #98.