Add new lives mode and more test options!

Users can now choose from two modes - lives and questions. Lives mode will end when the user makes the chosen number of mistakes. Questions mode will end when the user answers all questions correctly from a list of questions the length of which the user chooses.

src/TestStart.js

@@ -0,0 +1,36 @@
+import React from "react";
+import Loader from "./puff-loader.svg";
+
+export default function TestStart(props) {
+	return (
+		<>
+			<div className="overlay" onClick={props.hideTestStart}></div>
+			<div className="overlay-content options-list-overlay-content">
+
+				{
+					props.loading
+					?
+					<img className="button-loader" src={Loader} alt="Loading..." />
+					:
+					<>
+						{
+							// ["Classic", "Lives", "Countdown"].map((mode) =>
+							["Classic", "Lives"].map((mode) =>
+								<h3
+									key={mode}
+									onClick={() => props.showIndividualTestPrompt(mode.toLowerCase())}
+								>
+									{mode}
+								</h3>
+							)
+						}
+						<div onClick={props.hideTestStart}>
+							Cancel
+						</div>
+					</>
+				}
+
+			</div>
+		</>
+	)
+}