More specific views for logged in users

- Logged in users can now see their own profiles by clicking their first
name on the navigation bar

- Users must be logged in now to contribute to a campaign

- Users must be logged in as the creator to turn a campaign into a
venture

- Creators do not have the option to contribute to their own campaigns

- New pop window with slider to specify contribution when logged in as a
non-creator user and viewing a campaign's page