Interface Kit: Adjust max size and default alignment...

...on controls where it makes sense:
- BRadioButton and BCheckBox now return their preferred size as their
maximum.
- BRadioButton, BCheckBox and BTextControl now use left alignment by
default, as this is the most common use case for them.
Adjust apps to conform to previous layout changes.

The Deskbar and Time preferences were both relying on BCheckBox's
previous unlimited max width to get their containing BBoxes to be the
right size. Adjust the box constraints to make this happen at the level
of the box instead.