Implement kj::newTee()

Make it possible to configure HttpClient to not reuse connections at all.

Fix json-test on MSVC.

Fix tls-test for OpenSSL 1.1.1.

These errors apparently don't show up until the first read with 1.1.1, and may have different messages.

Apparently this landed on my Debian machine *today* and then all of the sudden the test was failing. I was so confused.

Resolve or defer all TODO(soon)s

Fix Android build/test issues.

More 0.7 fixes

Removed mgravell C# implementation from list

Two fixes for build failure on Android (resubmit)

Have not found a universal way to detect C11 and after some deliberation
__BIONIC__ seems to be a better choice for these cases.

Fix build error because DTTOIF function is not available.

Reorder ifdef checks in BTreeImpl::growTree to make posix_memalign the
default case and hide aligned_alloc behind feature test macro. This
covers more systems and actually fixes the compatibility with Android.

Make Canceler::isEmpty() const

Fixups for 0.7