Add Bazel build files for the tutorial (#269)

This also allows other Bazel projects to include rosjava_core as an
external repository, as instructed in README.md.

This uses https://github.com/johnynek/bazel-deps to describe the Maven
dependencies. As a result, 3rdparty/ contains autogenerated files, and
the other files contain a hand-written description of the BUILD.

bazel/repositories.bzl

+"""External dependencies for rosjava_core, excluding Maven dependencies.
+
+Maven dependencies must be added to the workspace with bazel-deps.
+"""
+
+def rosjava_repositories():
+  _maybe(native.http_archive,
+      name = "com_github_rosjava_rosjava_bootstrap",
+      sha256 = "3c59776a8c6e22232d07f29a686c0e5f401812ec27f59405711657d54a792c08",
+      strip_prefix = "rosjava_bootstrap-62f865dbe8a7830b21e054dc2a5ac7d2edc6eafe",
+      urls = [
+          "https://github.com/rosjava/rosjava_bootstrap/archive/62f865dbe8a7830b21e054dc2a5ac7d2edc6eafe.tar.gz",
+      ],
+  )
+
+
+def _maybe(repo_rule, name, **kwargs):
+  if name not in native.existing_rules():
+    repo_rule(name=name, **kwargs)

dependencies.yaml

+# If you edit this file, follow these instructions to generate the output
+# files:
+#
+# cd ..
+# git clone https://github.com/johnynek/bazel-deps
+# cd bazel-deps
+# bazel build src/scala/com/github/johnynek/bazel_deps:parseproject_deploy.jar
+# cd ../rosjava_core
+# ../bazel-deps/gen_maven_deps.sh generate -r $PWD -s 3rdparty/workspace.bzl -d dependencies.yaml
+
+options:
+  languages: [ "java" ]
+  resolvers:
+    - id: "jcenter"
+      type: "default"
+      url: https://jcenter.bintray.com/
+    - id: "rosjava_mvn_repo"
+      type: "default"
+      url: https://github.com/rosjava/rosjava_mvn_repo/raw/master
+  resolverCache: bazel_output_base
+  transitivity: runtime_deps
+  versionConflictPolicy: highest
+  buildHeader:
+    - "# Do not edit. bazel-deps autogenerates this file from dependencies.yaml."
+
+dependencies:
+  commons-pool:
+    commons-pool:
+      lang: java
+      version: "1.6"
+  com.google.guava:
+    guava:
+      lang: java
+      version: "12.0"
+  dnsjava:
+    dnsjava:
+      lang: java
+      version: "2.1.1"
+  io.netty:
+    netty:
+      lang: java
+      version: "3.5.13.Final"
+  junit:
+    junit:
+      lang: java
+      version: "4.8.2"
+  org.apache.commons:
+    com.springsource.org.apache.commons.codec:
+      lang: java
+      version: "1.3.0"
+    com.springsource.org.apache.commons.httpclient:
+      lang: java
+      version: "3.1.0"
+    com.springsource.org.apache.commons.io:
+      lang: java
+      version: "1.4.0"
+    com.springsource.org.apache.commons.lang:
+      lang: java
+      version: "2.4.0"
+    com.springsource.org.apache.commons.logging:
+      lang: java
+      version: "1.1.1"
+    com.springsource.org.apache.commons.net:
+      lang: java
+      version: "2.0.0"
+  org.apache.ws.commons:
+    ws-commons-util:
+      lang: java
+      version: "1.0.1"
+  org.mockito:
+    mockito-all:
+      lang: java
+      version: "1.8.5"
+  org.ros.rosjava_messages:
+    rosgraph_msgs:
+      lang: java
+      version: "1.11.2"
+    std_msgs:
+      lang: java
+      version: "0.5.11"

rosjava/BUILD.bazel

+java_library(
+    name = "rosjava",
+    srcs = glob([
+        "src/main/**/*.java",
+    ]),
+    visibility = ["//visibility:public"],
+    deps = [
+        "//3rdparty/jvm/com/google/guava",
+        "//3rdparty/jvm/dnsjava",
+        "//3rdparty/jvm/io/netty",
+        "//3rdparty/jvm/org/apache/commons:com_springsource_org_apache_commons_logging",
+        "//3rdparty/jvm/org/apache/commons:com_springsource_org_apache_commons_net",
+        "//3rdparty/jvm/org/ros/rosjava_messages:rosgraph_msgs",
+        "//3rdparty/jvm/org/ros/rosjava_messages:std_msgs",
+        "//apache_xmlrpc_client",
+        "//apache_xmlrpc_common",
+        "//apache_xmlrpc_server",
+        "@com_github_rosjava_rosjava_bootstrap//message_generation",
+    ],
+)

rosjava_tutorial_pubsub/BUILD.bazel

+java_binary(
+    name = "rosjava_tutorial_pubsub",
+    srcs = glob([
+        "src/main/**/*.java",
+    ]),
+    main_class = "org.ros.RosRun",
+    deps = [
+        "//3rdparty/jvm/org/apache/commons:com_springsource_org_apache_commons_logging",
+        "//3rdparty/jvm/org/ros/rosjava_messages:std_msgs",
+        "//rosjava",
+        "@com_github_rosjava_rosjava_bootstrap//message_generation",
+    ],
+)