Running Extensive tests. v0.1: release v0.2: keyboard compatibility v0.3: extra v0.4 delete system working v0.5 minor bug fixes and enter key pressed for = sign. v0.6 Extra bug fixes v0.7 Now take pi as a whole number, not NAN. v0.8 Implemented a new calculating engine. v0.9 Made functional exit button, rearranged calculator buttons to fit standards, and fixed background v0.9.1 Fixed glitch where the text remains after the window is closed
