swift234

make the big switch: {} are now statements, not expressions.  This removes some
annoying things from the grammar (like expr-non-brace), and makes it so that 
the body/else of an if is just a statement.

This patch has a fairly serious caveat that we just drop function bodies on the
floor now, since we have no "stmtexpr" sort of thing to represent the syntactic
sugar that is func.  We'll fix that soon.


Swift SVN r462