version: add ability to specify a version suffix
windows: properly close the default loop

Also close the IOCP handle for any loop.

Closes #393
test: add test for closing and recreating default loop
linux: try epoll_pwait if epoll_wait is missing

It seems that epoll_wait is implemented in glibc in terms of epoll_pwait and
new architectures (like arm64) do not implement the epoll_wait syscall at all.
So if epoll_wait errors with ENOSYS, just call epoll_pwait.
unix: fix warnings when loading functions with dlsym
unix: fix warnings about dollar symbol usage in identifiers
ignore: ignore Xcode project and workspace files
build: add m4 for feature/flag-testing
ignore: include m4 files which are created manually
build, gyp: set xcode flags
windows: improve timer precision

Improve timing precision by using QueryPerformanceCounter.

This is part of the fix for Node.js' test-timers-first-fire.js.
version: set version to 1.0.0-rc1
2014.09.18, Version 1.0.0-rc1 (Unstable)
version: now working on 1.0.0-rc2