Extend EventPort interface to support cross-thread wakeups.

This is not currently used, but eventually we'll use this to support efficient inter-thread messaging.

That said, I've decided that inter-thread messaging is complicated and I don't want to work on it right now.
Merge branch 'master' of github.com:kentonv/capnproto
Add hooks allowing a MessageBuilder to be initialized from existing memory.
Fix build on GCC.
Add an easier way to read a message directly into a builder. Requires a copy for security/validation.
Extend previous change for flat arrays as well.
Fixes #115
Minor fixes to comments in rpc.capnp

Remove a reference to Main, add a comment about the legality of acceptFromThirdParty, and fix a few typos and one pervasive grammatical error.
Support Android.
Add test scripts for MinGW and Android.
Update mega-test, and make tests pass.
Fix uninitialized memory usage found by valgrind.
De-flake timing-dependent test.
Update bootstraps.
MSVC: Fix issues so cmake build works.
Add cmake to exotic tests.
Move cmake files into c++ subdir.

The idea behind the directory organization was that we might have official implementations for other languages in other top-level directories, as siblings to the c++ directory. It seems implausible that we'd use CMake as a meta-build-system over all of these.

Another reason for this change is that the release tarball actually contains only the c++ subdirectory. We probably want to include cmake files in the release.
Include cmake files in automake dist.
Update release script to build Windows package.
Resolve TODO(now|soon) and remove KJ_DBG.