Simplify and inline ObjectWrap::Wrap
Inline and clean up ObjectWrap::Unwrap
Move ObjectWrap into its own file.
Remove handle from ObjectWrap constructor. add obj->Wrap(handle)
Simplify Attach/Detach in ObjectWrap
Remove ObjectWrap::InformV8ofAllocation. (Too messy/complex.)
This requires that onExit() is not called immediately upon receiving a
SIGCHLD. There could still be data in the pipez. So, instead just set a
flag and invoke the pipe watchers.
Sometimes one will not receive an EOF from pipes because the process was
killed by a SIGTERM, or something. If SIGCHLD has been recved but we are
getting EAGAIN, the pipez need to be closed too.