`activity.jsx`: Turned into "Matches" screen. Using `UserListItem` component (for now).

`app.jsx`: Wired up "Matches" screen, which replaces old "Activity" screen (accessed from side menu)

`remote.js`: New `remote.parse.choice.getMatchesByUserDataId` method; Storing `userData` in `remote.allUserData`; Adding `lodash` library (already in use in `react-screens.jsx`);

`sideMenu.jsx`: Minor rename: `handleActivityChange` --> `handleMatchesChange`

`userListItem.jsx`: Minor: removing unneeded `console.log`

`locations.jsx`: Minor, to support changes to "Matches"