Working on issue #6, fixed some UI

[tbeidlershenk]

Changes:

1. Created NavBar class to be used in multiple views (we can update this class if we want to change the navigation for all views)
2. Updated the UI for ListPage
3. Created PostCard class for an individual lost / found item
4. Updated PostPage class for displaying a lost / found item from the map view or list view in more detail (image, description, etc.)
5. Created routing class that we can control routing animations from (right now there's not really an animation) and should use for all app routing
6. Created a directory structure but I didn't move the unmodified files into it because I didn't want to mess up any local changes @jeffzheng13 has

Notes

• Color scheme is not set in stone I just picked one for designing the UI
• The PostCard and PostPage components generated by data returned from the database have some hard-coded data just to demonstrate the UI. We will have to update the datamodel and the database schema

[jeffzheng13]

Going to go ahead and merge the pull request, but will open a defect in the that routing the app is not super seemless. Clicking on the new page still registers clicks underneath the page (MapPage).