Add all build files to gitignore.

.gitignore

@@ -1 +1,24 @@
-build/
+# CMake
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+
+/libyaml-cpp.a
+/test/gmock-*/gtest/libgtest.a
+/test/gmock-*/gtest/libgtest_main.a
+/test/gmock-*/libgmock.a
+/test/gmock-*/libgmock_main.a
+/test/run-tests
+/util/parse
+/util/read
+/util/sandbox
+/yaml-cpp-config-version.cmake
+/yaml-cpp-config.cmake
+/yaml-cpp-targets.cmake
+/yaml-cpp.pc