Merge pull request #1891 from tbetbetbe/grpc-python-update-readme-install

Updates the INSTALL section for python

src/python/README.md

 gRPC Python
 =========
-
 The Python facility of gRPC.
 
-
 Status
 -------
-
 Alpha : Ready for early adopters
 
-Prerequisites
------------------------
-
-Python 2.7, virtualenv, pip, libprotobuf-dev, and libprotoc-dev.
-
+PREREQUISITES
+-------------
+- Python 2.7, virtualenv, pip
+- [homebrew][] on Mac OS X, [linuxbrew][] on Linux.  These simplify the installation of the gRPC C core.
 
-Building from source
-----------------------
+INSTALLATION
+-------------
+On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][].
+Run the following command to install gRPC Python.
+```sh
+$ curl -fsSL https://goo.gl/getgrpc | bash -s python
+```
+This will download and run the [gRPC install script][], then install the latest version of the gRPC Python package.  It also installs the Protocol Buffers compiler (_protoc_) and the gRPC _protoc_ plugin for python.
 
+BUILDING FROM SOURCE
+---------------------
+- Clone this repository
 - Build the gRPC core from the root of the
-  [gRPC git repo](https://github.com/grpc/grpc)
+  [gRPC Git repository](https://github.com/grpc/grpc)
 ```
 $ make shared_c static_c
 ```
@@ -29,40 +34,16 @@ $ make shared_c static_c
 $ tools/run_tests/build_python.sh
 ```
 
-
-Testing
------------------------
+TESTING
+-------
 
 - Use run_python.sh to run gRPC as it was installed into the virtual environment
 ```
 $ tools/run_tests/run_python.sh
 ```
 
-
-Installing
------------------------
-
-- Install the gRPC core
-  - [Debian package](https://github.com/grpc/grpc/releases)
-    ```
-    $ wget https://github.com/grpc/grpc/releases/download/release-0_5_0/libgrpc_0.5.0_amd64.deb
-    $ wget https://github.com/grpc/grpc/releases/download/release-0_5_0/libgrpc-dev_0.5.0_amd64.deb
-    $ sudo dpkg -i libgrpc_0.5.0_amd64.deb libgrpc-dev_0.5.0_amd64.deb
-    ```
-  - [From source](https://github.com/grpc/grpc/blob/master/INSTALL)
-
-- Install gRPC Python's dependencies
-```
-$ pip install -r src/python/requirements.txt
-```
-
-- Install gRPC Python
-```
-$ pip install src/python/src
-```
-
-Packaging to PyPI
------------------------
+PACKAGING
+---------
 
 - Install packaging dependencies
 ```
@@ -73,3 +54,7 @@ $ pip install setuptools twine
 ```
 $ ../../tools/distrib/python/submit.py
 ```
+
+[homebrew]:http://brew.sh
+[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
+[gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install