Fixed icon switching for preview and editing and added tooltips to avoid some confusion as to what clicking the button actually does.
Added currentDate member var to the Diary class and use it to set up the date on a new diary.
Added beginning of the function that reads the day from the DB and added
simple list to keep track of the tags that are tagged to the day.
Fixed typo in Diary
Added stub function to change the day when the calendar is clicked.