Reduce bundle size

- Use the browsers fetch rather than the request module
 - base64-loader -> raw-loader
 - Remove ol3 because it's been broken for a while
 - Removed old GitHub gist support as it's no longer functional
 - Removed Mousetrap as we were only using a small part of the functionality
 - Moved to single js file to make things simplier

src/components/modals/SettingsModal.jsx

@@ -107,7 +107,7 @@ class SettingsModal extends React.Component {
           data-wd-key="modal-settings.maputnik:renderer" 
           options={[
             ['mbgljs', 'MapboxGL JS'],
-            ['ol3', 'Open Layers 3'],
+            // ['ol3', 'Open Layers 3'],
           ]}
           value={metadata['maputnik:renderer'] || 'mbgljs'}
           onChange={this.changeMetadataProperty.bind(this, 'maputnik:renderer')}