Apply 1.5-rc1 cherry-picks. (#16056)

* Delete empty api_guides.

PiperOrigin-RevId: 179215745

* Java: Instructions for using GPUs via Maven.

GPU support in Maven is being packaged with 1.5.0-rc0 onwards
(for Linux)

Fixes #12909

PiperOrigin-RevId: 180859336

* Fix build issues with cuda 9.1 through updating eigen. (#15796)

* Revert "Fix the headers error due to recent CUDA9.1 change (#15739)"

This reverts commit 3bc4900e.

* Bump eigen dependency.

* Minor change to make tpu.rewrite compatible with Python 3.

AttrValue is a byte array, and handling this is different between Python 2 and 3.

PiperOrigin-RevId: 180306415

* TensorFlow for NVIDIA Tegra devices with CUDA support (#14167)

This commit enables CUDA support on compatible devices running Android such as the Nvidia TX1 and TX2 when using Makefile builds.

Note that JetPack for Android is required to build/run Android TF binaries with CUDA support. This should be released by Nvidia in the near future.

* Adding cuda_config.h to the pip package. (#15961)

* Adding cuda_config headers to our GPU build.

* Updating the local cuda path for cuda_headers.

* Removing the cuda_config blacklist.

* Buildifier fix.

* Ignoring .so files and manually adding the cuda_config.h file.

* Fixing the path for the src_dir.

* One last minor fix for path.

* Adding brackets.

* Minor fixes for "Linear" tutorial

PiperOrigin-RevId: 179061248

* Sync Premade and Custom estimator docs with example code.

PiperOrigin-RevId: 179404175

* rename files

PiperOrigin-RevId: 179683700

* Modernize old "get_started/get_started.md", as "programmers_guide/low_level_intro.md".

PiperOrigin-RevId: 179807033

* Add links to low level API intro

PiperOrigin-RevId: 179844300

* Make images larger

PiperOrigin-RevId: 181034398

* minor fixes to new "low_level_intro"

PiperOrigin-RevId: 181172455

* typo

PiperOrigin-RevId: 181185642

* Replace get_started

Also add sub-sections to leftnav files,
and sync leftnav and index files.

PiperOrigin-RevId: 181394206

* Added a "Getting Started with TensorFlow for ML Beginners" chapter to Get
Started section.

PiperOrigin-RevId: 181396430

* Add support for CUBLAS_TENSOR_OP_MATH in fp16 GEMM (#13451)

- Applies to matrix multiplications with fp16 input/output.
  Computations will fall back to pseudo-fp16 if tensor op math is
  disabled or not supported.
- Enabled by default. Tensor ops (both in cublas gemms and cudnn
  convolutions) can be disabled globally by setting the
  environment variable TF_DISABLE_TENSOR_OP_MATH=1. To disable
  tensor ops specifically for gemms or convolutions use
  TF_DISABLE_CUBLAS_TENSOR_OP_MATH=1 or
  TF_DISABLE_CUDNN_TENSOR_OP_MATH=1, respectively.
- Added CUBLAS 9.0 algorithms to GetBlasGemmAlgorithms().

* Adding page to tensorflow.org with directions for building the TFLite demo on Android.

PiperOrigin-RevId: 179970218