nghttpx: Pool http downstream connection per thread
nghttpx: Apply same fix from a225bb2 to spdy upstream
src: Fix possible heap-use-after free for OpenSSL global locking

This is simply programming error, but it is interesting that using
libstdc++ does not reveal this error.  With clang++-libc++, we got
std::system_error: mutex lock faild: Invalid argument.  This is
because we did not give a name to lock object, so it is immediately
destructed.  I think this will fix the reported crash on Mac OSX.
tiny-nghttpd: Simplify timer event handling
Bump up version number to 0.6.4

Library code has not changed at all since the last release, so LT
revision stays the same.
Update man pages
Bump up version number to 0.6.5-DEV