swift234

Various inout improvements:
 - purge @inout from comments in the compiler except for places talking about
   the SIL argument convention.
 - change diagnostics to not refer to @inout
 - Change the astprinter to print InoutType without the @, so it doesn't show
   up in diagnostics or in closure argument types in code completion.
 - Implement type parsing support for the new inout syntax (before we just 
   handled patterns).
 - Switch the last couple of uses in the stdlib (in types) to inout.
 - Various testcase updates (more to come).



Swift SVN r13564