win/udp: make uv_udp_set_socket set UV_HANDLE_IPV6

This patch makes uv_udp_set_socket responsible for setting the
UV_HANDLE_IPV6 flag. It also fixes the problem that uv_udp_open would
never set this flag at all.

In addition, this patch fixes some minor style issues.
win/udp: fix bug in getsockopt() return value check
win/udp: DRY up setting SO_REUSEADDR

This patch makes sure that only uv_udp_set_socket sets the SO_REUSEADDR
bit for UDP sockets.
win: get rid of early ipv6 support detection

No longer explictly check wheter an IPv6 stack is present when the user
tries to use IPV6 sockets. Instead realy on the operating system
to report the lack of protocol support via appropriate error messages.
unix: don't clobber errno in signal handler
build: fix up WIN_SRCS
do not compress private keys - changed terminologiy from verify/sign to public/private
changed readme and test with performance figures
more work
added scalar addition
added scalar in types
little docs improvements
added warning about last bit being ignored on scalars
Update readme.md
fixed DLL exports
darwin: merge uv_cond_timedwait implementation

Merge the OS X specific implementation of uv_cond_timedwait() with the
generic one. The only difference is that it now uses mach_absolute_time
instead of gettimeofday.
Revert "darwin: merge uv_cond_timedwait implementation"

Using mach_absolute_time() for the pthread_cond_timedwait() timeout
breaks a number of tests on OS X 10.8.2.

This reverts commit 8311390f13177f3086ecdac875115d2d4cc2688b.
unix: remove scandir prototype workaround in fs.c

It's not necessary for newer OS X releases and I don't care enough
about OpenBSD to squelch the warning.
darwin: merge uv_cond_timedwait implementation

This is a revised version of commit 8311390.
win: Avoid using subversion to download gyp