Remove '-mfpu=neon' GCC compiler option

The newer versions of TensorFlow use
[`Eigen::half`](https://eigen.tuxfamily.org/dox-devel/Half_8h_source.html)
to allow for 16-bit floating point operations. Unfortunately, these are
not compatible with the NEON instruction set. To keep things simple
(and functioning), the final `bazel build` step for creating the
TensorFlow wheel no longer has `--copt="-mfpu=neon"` included.

Author: samjabrahams

GUIDE.md

@@ -270,20 +270,6 @@ cd tensorflow
 
 _Note: if you're looking to build to a specific version or commit of TensorFlow (as opposed to the HEAD at master), you should `git checkout` it now._
 
----
-
-#### NOTE: TensorFlow 0.9 compilation failing
-
-As of June 10, 2016, there are issues with the build process for more recent commits in the TensorFlow repository. Most notably, the [0.9 release candidate 0](https://github.com/tensorflow/tensorflow/releases/tag/v0.9.0rc0) will not build. This is due to changes related to 16-bit floating point support. The most recent confirmed build was branch `r0.8`. If you'd like to build TensorFlow 0.8, run this command once inside of the TensorFlow directory:
-
-```
-git checkout r0.8
-```
-
-This notice will be removed once the problem is removed or a fix is found.
-
----
-
 Once in the directory, we have to write a nifty one-liner that is incredibly important. The next line goes through all files and changes references of 64-bit program implementations (which we don't have access to) to 32-bit implementations. Neat!
 
 ```shell
@@ -307,7 +293,7 @@ _Note: if you want to build for Python 3, specify `/usr/bin/python3` for Python'
 Now we can use it to build TensorFlow! **Warning: This takes a really, really long time. Several hours.**
 
 ```shell
-bazel build -c opt --local_resources 1024,1.0,1.0 --verbose_failures --copt="-mfpu=neon" tensorflow/tools/pip_package:build_pip_package
+bazel build -c opt --local_resources 1024,1.0,1.0 --verbose_failures tensorflow/tools/pip_package:build_pip_package
 ```
 
 _Note: I toyed around with telling Bazel to use all four cores in the Raspberry Pi, but that seemed to make compiling more prone to completely locking up. This process takes a long time regardless, so I'm sticking with the more reliable options here. If you want to be bold, try using `--local_resources 1024,2.0,1.0` or `--local_resources 1024,4.0,1.0`_