Python: Use "build" instead of "build_ext" in scripts (#460)

Previously, the Python package consisted of a single extension
module, so `build_ext` was sufficient.  Now, the package
contains a native module and an extension module, so both
`build_py` and `build_ext` are required.  Instead, run `build`,
which calls both `build_py` and `build_ext` automatically.

.travis.sh

@@ -39,7 +39,7 @@ case "$1" in
 		if [ "${TRAVIS_OS_NAME}" = "osx" ]; then
 			source venv/bin/activate
 		fi
-		python setup.py build_ext test
+		python setup.py build test
 		;;
 	esac
 	;;

README.md

@@ -53,7 +53,7 @@ See [Premake5](https://premake.github.io/)
 
 The basic commands to build, test, and install the Python module are:
 
-    $ python setup.py build_ext test
+    $ python setup.py build test
     $ python setup.py install
 
 See the [Python readme](python/README.md) for more details.

python/README.md

@@ -7,7 +7,7 @@ This directory contains the code for the Python `brotli` module,
 To build the module, execute the following from the root project
 directory:
 
-    $ python setup.py build_ext
+    $ python setup.py build
 
 To test the module, execute the following from the root project
 directory: