added basic tests

removed extra dependencies

fixed negative trig function bug

Fixed display bug, changed colors, and changed button locations, added font

Added singleton functionality

added a few more comments

added comments for clarity

calculation bugfixes

refactored EvaluateExpression to handle more complex inputs

Bug fixes, added unary operator full functionality

fixed project directory

updated readme and include file

added files and updated readme

added readme to main folder

added readme file for installation