This is also in preparation for the writev patch, which needs to dump
remaining data after ev_loop ends.

This reverts commit 564a4864.

Breaks cygwin

There was the possibility the buffer could be GCed while the eio_req was
pending.  Still needs test coverage for the fs.read() problem.

See:
http://groups.google.com/group/nodejs/browse_thread/thread/c11f8b683f37cef

Revert "Add ~/.node_modules as well as ~/.node_libraries"

This reverts commits
5e14c8be.
b0adaff6.
492fc0d7.

Add a createScript function, and put stuff on exports instead of hiding
it in exports.Script.

1. Express desired path.join behavior in tests.
2. Update fs.realpath to reflect new path.join behavior
3. Update url.resolve() to use new path.join behavior.

writeFileSync could exhibit pathological behavior when a buffer could
not be written to the file in a single write() call.

Also, writeFile was not quite as optimized as it could be.