(models) replaced isCast by isExprResize
(transformations) removed constant folding of unary not for now
(vhdl) extracted VHDL-specific typing into VhdlTyper
(transformation) corrected bug with ExprUnary
(vhdl) cleaned up expression printer
(models) added another 'cast' method to allow force resize or not
(vhdl) corrections related to signed and narrower conversion
(vhdl) corrected infinite recursion (oops)
(hdl) a few corrections to typing
(vhdl) corrected a bug with single-action schedule
(hdl) special case for resize of integers