Update cursor used with navbar elements

Modified CSS so the pointer cursor is only shown over the "Sign Out"
button.
Move position of "wrench" icon in ModelTree

Position flush with bottom of top border of ComponentCell.
Add box shadows to all dialog boxen

Added for consistency, since PopupPanels (used in drop-down menus) have
them. And they look nice.
Use pointer cursor with all buttons and droplists

Also use for ComponentCell in ModelTree.
Show default cursor over labels in dialog boxes

Previously, the I-beam cursor was displayed.