With CAPNP_LITE=1, the command-line tools will not be built, and the
tests cannot be built without EXTERNAL_CAPNP=1 (BUILD_TESTING=0 needs to
be set if the tests are not desired).

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

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

For portions currently copyright by Kenton (most of it), transfer copyright to Sandstorm Development Group, Inc. (Kenton's company).

The license change is practically meaningless, as MIT and BSD 2-clause are legally equivalent. However, the BSD 2-clause license is sometimes confused for its ugly siblings, BSD 3-clause and BSD 4-clause. The MIT license is more immediately recognizeable for what it is.

Rémy Blank and Jason Choy (the two non-trivial contributors) are on record as approving this change:

https://groups.google.com/d/msg/capnproto/xXDd2HUOCcc/gbe_COIuXKYJ

Add ability to truncate a list post-allocation and reclaim space. Currently limited to blobs and can only be accessed through the Orphan interface.

- Define separate times for durations vs. absolute times.
- Make more consistent with existing precedents in KJ style.

Apparently writev() imposes a limit on the vector size.  Work around that.  Not sure why libc doesn't already do this.

Extend FlatArrayMessageReader to indicate where the message actually ended, in case it was not the end of the array.  Useful when reading an mmap'd file with a Cap'n Proto prefix.  Also fix a bug in Maybe dealing with DisallowConstCopy subclasses.