_List of Desired Features_

Categories work based on selection, not just highlight
 - i.e. assign categories to multiple books at once
 - this may involve extra logic if books don't have the same categories beforehand
Search ignores Case
Regex Search
Choose shown columns in browser
Support for multiple copies
Text entry supports longer string
 - implementation started in gui.py
Home and End navigate to top and bottom of catalogue respectively.


_Code Quality Improvements_
Document all functions
Conform to python naming conventions and code style
Make db_layer use a helper function to handle most of the database queries


_Bugs_
Error when entering bad ISBN e.g. 02010798X (instead of 020107981X)
 - seems to be an intermittant error, likely related to polling openLibrary
When the top element shown is highlighted in the browser window, and pgUp is pressed (causing a scrollup), the bottom border of the window turns into 'qqqqqqqq'.
 - does not happen when up_arrow is pressed.




_Implemented Features_
Sort by column in browser
Support UTF-8 for everything