Remove .sb from file browser filter since we can't support them yet. Remove...

Remove .sb from file browser filter since we can't support them yet. Remove .zip from the same. Save project as .sb3 (and untitled-project).

src/components/load-button/load-button.jsx

@@ -26,7 +26,7 @@ const LoadButtonComponent = ({
             </ButtonComponent>
             <input
                 disabled
-                accept=".sb,.sb2,.sb3,.zip"
+                accept=".sb2,.sb3"
                 className={styles.fileInput}
                 ref={inputRef}
                 type="file"

src/containers/save-button.jsx

@@ -28,7 +28,7 @@ class SaveButton extends React.Component {
             const date = new Date();
             const timestamp = `${date.toLocaleDateString()}-${date.toLocaleTimeString()}`;
             // TODO change extension to sb3
-            saveLink.download = `project-${timestamp}.zip`;
+            saveLink.download = `untitled-project-${timestamp}.sb3`;
             saveLink.click();
             window.URL.revokeObjectURL(url);
             document.body.removeChild(saveLink);