Add loadCompiledTypeAndDependencies() to SchemaParser so that compiled constants can be cast to static types.

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

I decided that consistent output across platforms is an important property, worth sacrificing a little bit of performance on MIPS.

Fix problem with the sockaddr struct.

Otherwise, at least clang++, forward-declares it inside the namespace `::capnp` and doesn't match it with a real `struct sockaddr` from the header 'socket.h'.

Also, accept `const` pointer - there is no point not to do so.

capnpc-capnp: keep list of extended interfaces.

Fix two typos in bit operations.

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

fix some error messages

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

Make it possible for a message builder to incorporate a byte array not owned by it without copying.  Useful for injecting large data blobs into a message without copying their contents.  Access this functionality through the Orphanage interface.