contributed by Peter Rosenberg:
- changed list item layout of spinners to new list_item_spinner
- replaced spinner for type with radio buttons in event edit dialog
- changed list item layout of event list to new list_item
- centered time picker of event horizontally

git-svn-id: file:///home/svnroot-zephyrsoft/projects/trackworktime/trunk@512 f37aa4ac-6963-46a2-a1ff-558a307fa857