message: Fixing some wording and specifying a clean env
diff: @@ -39,9 +39,9 @@ People who are a little more adventurous can also try our nightly binaries:
  **Nightly pip packages**
  * We are pleased to announce that TensorFlow now offers nightly pip packages
  under the [tf-nightly](https://pypi.python.org/pypi/tf-nightly) project on pypi.
  -Simply run `pip install tf-nightly` to install nightly tensorflow build. We
  -currently only support CPU-only packages on Linux and Mac. GPU packages on all
  -platforms and Windows CPU-only packages will arrive soon!
  +Simply run `pip install tf-nightly` in a clean environment to install the nightly
  +tensorflow build. We currently only support CPU-only packages on Linux and Mac.
  +GPU packages on all platforms and Windows CPU-only packages will arrive soon!
  **Individual whl files**
  