R0.8 tensorforest cherry-pick

One more version update for 0.8.0 final

Change: 120123078

Merge internal changes

Doc changes

Took out James Wexler (Googler) and added Yuan Tang (not Googler).

Took out James Wexler (Googler) and added Yuan Tang (not Googler).

for PIP installs.

(Also cherry-pick anaconda instructions)

They haven't been uploaded yet, and so our website is pointing people at the wrong location.

Fixed bug in `tf.train.ClusterSpec` constructor.

0.8.0rc0 --> 0.8.0

Creating a `tf.train.ClusterSpec` from another ClusterSpec was broken,
which in turn broke creating a `tf.train.Server` from a ClusterSpec.

Fixes #1961.
Change: 119954117

Fix TensorBoard lib/css dependency (#1926)

Change: 119605636

update more places with version to 0.8

Add 0.8 release notes

Make sparse_tensor_dense_matmul_op_test medium

Fixes for release

* Made the indexing operator accept objects that can be converted with `int()`.

Previously, the `_SliceHelper()` would test for `isinstance(..., int)`, which
is too restrictive.

* Replace `np.random.random_integers()` with `np.random.randint()`

Removes high rank and large tensors from the test.

version_test.py: patch can be alphanumeric (e.g., 0rc0)

Removes high rank and large tensors from the test.

* Update TF Mechanics 101 Tutorial to match recent code
In the section of Inputs and Placeholders, the IMAGE_PIXELS should be mnist.IMAGE_PIXELS

* Moved mnist reading from input_data in tutorial to learn/datasets