Refactor .gitignore files

.gitignore

+# emacs backup file
 *~
-*.o
-*.lo
+
+# autotools
 *.la
-depcomp
+*.lo
 *.m4
+*.o
+.deps/
+.libs/
+INSTALL
 Makefile
 Makefile.in
-libtool
-missing
 autom4te.cache/
+compile
 config.guess
 config.h
 config.h.in
@@ -16,37 +20,14 @@ config.log
 config.status
 config.sub
 configure
+depcomp
 install-sh
-.deps/
-.libs
-lib/includes/nghttp2/nghttp2ver.h
-lib/libnghttp2.pc
-src/libnghttp2_asio.pc
+libtool
 ltmain.sh
+missing
 stamp-h1
-.deps/
-INSTALL
-.DS_STORE
-compile
 test-driver
-.dirstamp
-doc/index.rst
-doc/nghttp2.h.rst
-doc/nghttp2ver.h.rst
-doc/package_README.rst
-doc/tutorial-client.rst
-doc/tutorial-server.rst
-doc/nghttpx-howto.rst
-doc/h2load-howto.rst
-doc/tutorial-hpack.rst
-doc/python-apiref.rst
-doc/building-android-binary.rst
-doc/asio_http2.h.rst
-doc/asio_http2_server.h.rst
-doc/asio_http2_client.h.rst
-doc/libnghttp2_asio.rst
-doc/contribute.rst
-python/setup.py
-python/dist
-python/MANIFEST
-integration-tests/config.go
+
+# test logs generated by `make check`
+*.log
+*.trs

doc/.gitignore

+# generated files
 apiref.rst
+asio_http2.h.rst
+asio_http2_client.h.rst
+asio_http2_server.h.rst
+building-android-binary.rst
 conf.py
-manual
+contribute.rst
+h2load-howto.rst
+index.rst
+libnghttp2_asio.rst
+manual/
+nghttp2.h.rst
+nghttp2ver.h.rst
+nghttpx-howto.rst
+package_README.rst
+python-apiref.rst
+tutorial-client.rst
+tutorial-hpack.rst
+tutorial-server.rst

integration-tests/.gitignore

+# generated files
+config.go

lib/.gitignore

+# generated files
+includes/nghttp2/nghttp2ver.h
+libnghttp2.pc

python/.gitignore

+# generated files
+MANIFEST
+dist/
+setup.py

src/.gitignore

+# generated files
+libnghttp2_asio.pc
+
+# programs
+deflatehd
+h2load
+inflatehd
 nghttp
 nghttpd
 nghttpx
-nghttpx-unittest
-nghttpx-unittest.log
-nghttpx-unittest.trs
-test-suite.log
-.dirstamp
+
+# build
 libnghttpx.a
-deflatehd
-inflatehd
-h2load
+
+# tests
+nghttpx-unittest

tests/.gitignore

-test-suite.log
+# tests
 failmalloc
-failmalloc.log
-failmalloc.trs
 main
-main.log
-main.trs

third-party/http-parser/.gitignore

+.dirstamp