Calculator

This is a basic calculator for watches and eventually bike computers. Currently it is only enabled for use on watches with a round screen and there are apparently issues with the Vivoactive 3. AGAIN, DOES NOT WORK WELL WITH VIVOACTIVE 3 INSTRUCTIONS FOR USE: * On devices without a touch screen, the app relies on the accelerometer to provide tilt controls. ----A small moving reticle should appear which is to act as the cursor to "click" buttons. ----Clicking is accomplished by pressing the Select/Start/Enter button. * On devices with touch screens, bringing up the main menu should present an option to enable touch select. ----Touch select mode is experimental for now, it is not guaranteed to work. * Evaluating the current operation ('=' equivalent) is accomplished by either clicking the text box where the numbers are displayed, pressing the down button, or swiping up on touch screen devices. * Clearing the current entry is accomplished by either clicking the 'C' at the top center of the screen, pressing the up button, or swiping down on touch screen devices. * The left arrow button in the top left will delete the last entered, right most digit. * The '+/-' button flips the sign of the current number. * The 'pi' button will enter in the value of pi. * The 'sqrt' button will take the square root of the entered number. * The '^2' button will square the entered number. * While a maximum of 4 decimal places are displayed on results, that truncation has not occurred internally. KNOWN ISSUES: * May be difficult to see in low light conditions EVENTUAL ADDITIONS (no order): * More devices * RPN mode * Control of precision * Invert tilt controls * Control of tilt sensitivity * Additional operators + constants