Result -> Results

See changes to test.capnp for example.

Currently only supported through generated code, not in the dynamic API. Not exactly sure how to expose this in the dynamic API...

fix copy-paste bug in TestRpc_TailCall: add missing assertion

Note that embedded schema structures in generated code are still incorrect.

CMake improvements

initial fixes for building kj/main.c++ utilities on mingw

Remove '-d' flag from call to atos(1)

That is to say, whereas previously we would extend capnp::typeId<T>() to a new type by declaring a specialization of it for that type, now we instead have the type contain a nested class called _capnpPrivate which contains a `typeId` constant.

This is necessary because it is impossible to specialize a template for a type which is itself nested inside a template type. E.g. it's impossible to write a specialization `template <typename T> typeId<Foo<T>::Bar>()`; C++ simply doesn't support this. But with generics, Cap'n Proto will allow types to be nested inside templates, so we need this to work.

atos(1) doesn't actually have a '-d' flag, but its inclusion was
innocuous (and suppressed a warning) until OS X 10.10.

1) Apparently mixing member defaults and initializer lists is a C++14 thing.
2) My test script compiles with -Werror which errors out on calls to now-deprecated getDependency().

More refactoring is needed, but this at least makes "using" aliases work correctly with generics.

This function now (on windows):
* converts \n to \r\n (for both file and console outputs)
* when the output is redirected to a file, uses WriteFile with utf-8 output
* when the output will appear on a console, uses WriteConsole with utf-16 output instead

add fix for older cmake versions