swift234

A long journey later, implement support for type inference of integer literals instead of
forcing them to int64 all the time.  Now the integer_literal_type in the standard library
is only used to resolve ambiguity in expressions.  Among other amazing things, we now
correctly accept:

  var x8 : int8 = 4

without a cast.

This still isn't doing any bounds checking and isn't checking the inferred type to tell if
it is compatible with integer literals (i.e. has a primitive conversion function from the
LLVM IR type).  Enough for now though.

This is progress towards rdar://10357238.



Swift SVN r814