Makes flags non-selectable + clickable (#212)

src/components/green-flag/green-flag.css

@@ -3,6 +3,7 @@
     height: 1.1rem;
     opacity: 0.5;
     margin: 0.25rem 0.6rem;
+    user-select: none;
     cursor: pointer;
     transition: opacity 0.2s ease-out; /* @todo: standardize with var */ 
 }

src/components/stop-all/stop-all.css

@@ -2,6 +2,8 @@
     width: 1.1rem;
     height: 1.1rem;
     opacity: 0.5;
+    user-select: none;
+    cursor: pointer;
     transition: opacity 0.2s ease-out; /* @todo: standardize with var */ 
 }