Books go into the booklist now. Saves a lot of unnecessary updates.
Fixed sorting bug on customerTab
BookDialog: added lots of functionality (delete, etc)
Added Exit-Button/Functionality on main dialog
BookTable: added Shelf (according to Scenario 1)
...
Close Main Windows --> Close everything.
fixed a bug that made opening a loan impossible. Sorry bro.
started with LoanDetail
cleanUp on BookTab and LoanTab
LoanDetail WIP
Splashscreen!
clean up imports
Added icons to tabs
Merge branch 'dev' of git@github.com:LePhil/Bibliotheca.git into dev

Conflicts:
	src/views/MainView.java
added copy panel to loandetail
Made TitledBorders look the same
Enabled switching tabs by pressing Alt-1 to Alt-3
Added icons on buttons (add-buttons)
added more icons (show selected, close, search field)
added copy table in loan detail view
customer switch is working; add new loan is working;
gridbaglayout in invTop in all 3 tabs