move NEWS to top-level

Summary: @​ori was chastising me that we needed release notes, and then I showed him this file. He was happy it was here but wanted it be more discoverable.

Reviewed By: @jdelong

Differential Revision: D1590325
make test runner not puke when run with xargs

Summary: this has always bothered me. I basically copied http://gitelephant.cypresslab.net/symfony-2/commit/4f93d1adddeddbe6d0fdb56335d8c6dc6e3a6ad1

Reviewed By: @paulbiss

Differential Revision: D1591557