Cleanup

No big changes, just some cleanup.
- fixed delete spell book message box to show correct message
- added text to main form
- Made global SQLiteCommand instance
- removed all "this." for consistency's sake
- combined fillDatabase and addRowsToDatabase since they always go
together
- removed group box enabling and disabling code which is no longer used
Revert "Cleanup"

This reverts commit a043a30b289e88c7ea6c4590b308a7ae7bf75867.
Cleanup... Attempt 2

Ignore previous two commits... I screwed up.

No big changes, just some cleanup.
- fixed delete spell book message box to show correct message
- added text to main form
- made global SQLiteCommand instance
- removed all "this." for consistency's sake
- combined fillDatabase and addRowsToDatabase since they always go
together
- removed group box enabling and disabling code which is no longer used