yahns 1.7.0 - rack.hijack improvements and more

Nothing really significant, so there's no need to upgrade if
you're not affected by the minor fixes and changes in this
release.

For all users, LoadError and SyntaxError exceptions are now
logged and non-fatal within worker threads serving application
code.  Thanks to Lin Jen-Shin <godfat@godfat.org> for bringing
this up on the mailing list.

Additionally, temporary files buffered to the filesystem will
now support the Rack::TempfileReaper middleware in rack 1.6+

For rack.hijack users, there are some changes and improvements.
rack.hijack should return a usable IO-like object for SSL users,
now.  The rack.input object is no longer closed on hijacking,
allowing apps to continue using buffered input after hijacking.
There is also a bugfix for the rare apps which hijack requests
after emitting 100-continue responses.

Note: there is also a work-in-progress and under-documented
asynchronous Yayns::ProxyPass Rack app which uses rack.hijack
internally.  This will allow yahns to act as a fully-buffering
reverse proxy to upstream servers which cannot handle slow
clients.  Yahns::ProxyPass NOT production-ready as of this
release.  The old, synchronous extras/proxy_pass.rb code
remains usable.

There's also the usual round of minor code bloat reduction.