Clean up default macros and constants

src/calc.rs

@@ -80,13 +80,6 @@ impl Default for Calculator {
             state: CalculatorState::Normal,
             stack: vec![1.0, 2.0].into_iter().collect(),
             macros: [
-                (
-                    'e',
-                    CalculatorMacro {
-                        help: String::from("Empty"),
-                        value: String::from(""),
-                    },
-                ),
                 (
                     'm',
                     CalculatorMacro {
@@ -95,7 +88,7 @@ impl Default for Calculator {
                     },
                 ),
                 (
-                    'u',
+                    'Q',
                     CalculatorMacro {
                         help: String::from("Quadratic Formula"),
                         value: String::from(