Api for polling external sockets

Unix: namespace stream handle flags

linux: fix build error with old kernel headers

O_CLOEXEC was introduced in linux 2.6.23, don't assume it's available.

Fixes #400.

Windows: add uv_msafd_poll, to support overlapped socket polling

Windows: fetch pointer for CancelIoEx on startup

Windows: we're out of handle flags - arrange them more efficiently

Merge branch 'v0.6'

windows: map ERROR_WRITE_PROTECT to UV_EROFS

unix: map `EROFS` to `UV_EROFS`

Conflicts:

src/unix/error.c

err: handle EIO errors on win/unix

Merge branch 'v0.6'

Windows: map ERROR_NOT_SAME_DEVICE to UV_EXDEV

Windows: fix uv_fs_ftruncate to compile with Mingw32

Close: #382, #397
Ref: #381

Windows: always enable multicore compile

Windows: disable minimal rebuild (/Gm)

If enabled multicore compile doesn't work.

test-spawn failed to build on linux

- added missing header file
- converted c++ style comment to c style comment

test-spawn failed to build on linux

- added missing header file
- converted c++ style comment to c style comment

linux: add IN_MOVE_SELF to inotify event mask

Partially fixes joyent/node#3172, behavior is now consistent with inotifywait.

Test for the uv_spawn's setuid and setgid options

uv_spawn: support setting the child process' user and group id

Windows: add mappings for UV_ENOENT

Map ENOMEM to UV_ENOMEM

Windows: uv_spawn2 reports the wrong error when setuid/setgid is specified

Windows: add mappings for UV_ENOENT

Test for setuid/setgid