2006-03-30  Morten Welinder  <terra@gnome.org>

	* src/expr.c (negate_value): Simplify.
	(bin_arith): Simplify and handler overflow better.

	* src/cell.c (cell_is_zero): Simplify.

	* src/gui-util.c (entry_to_int): Accept floating point values as
	long as they hold integers of the right magnitude.