Graphical update.

- Added an update to about half the buttons. I'll finish up the rest
later (and hopefully you guys can grab what I miss). The color is
temporary, though I was thinking we might want to use lighter shades
seeing as this is some sort of disaster relief program.
- Small layout fixes (mostly adding linear layouts for symmetry
reasons).
- Main activity now has a picture, which is also temporary. I have one
tuned to our application on the way.
- Preliminary work done for "Found an Item" and "Lost an Item". These
will link to add item pages with the "lost" and "found" types being
determined respectively. Whenever they are submitted, the program should
automatically try to match them with the opposite type that share
attributes.