Update samplerobot python unittest

[snozawa]

samplerobotのpythonサンプルのテストがunittestになってなくて、
えらーがおきてもrostestのrespawnが走らなかったので、unittestにしました。
また、出力がかくされますが、.travis.shのなかでエラーしたときに
出力をprintする箇所でrosunitの各テストの標準出力・エラー出力を出すようにしました。

[k-okada]

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http:https://jenkins.jsk.imi.i.u-tokyo.ac.jp:8080/job/hrpsys-qnx/2479/

Build Log
last 10 lines

[...truncated 3712 lines...]
    at org.jenkinsci.plugins.ghprb.GhprbRepository.createCommitStatus(GhprbRepository.java:122)
    at org.jenkinsci.plugins.ghprb.GhprbBuilds.onCompleted(GhprbBuilds.java:118)
    at org.jenkinsci.plugins.ghprb.GhprbBuildListener.onCompleted(GhprbBuildListener.java:27)
    at org.jenkinsci.plugins.ghprb.GhprbBuildListener.onCompleted(GhprbBuildListener.java:12)
    at hudson.model.listeners.RunListener.fireCompleted(RunListener.java:201)
    at hudson.model.Run.execute(Run.java:1783)
    at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
    at hudson.model.ResourceController.execute(ResourceController.java:98)
    at hudson.model.Executor.run(Executor.java:410)

Test FAILed.

[k-okada]

Refer to this link for build results (access rights to CI server needed):
http:https://jenkins.jsk.imi.i.u-tokyo.ac.jp:8080/job/hrpsys-qnx/2480/

Build Log
last 10 lines

[...truncated 3712 lines...]
    at org.jenkinsci.plugins.ghprb.GhprbRepository.createCommitStatus(GhprbRepository.java:122)
    at org.jenkinsci.plugins.ghprb.GhprbBuilds.onCompleted(GhprbBuilds.java:118)
    at org.jenkinsci.plugins.ghprb.GhprbBuildListener.onCompleted(GhprbBuildListener.java:27)
    at org.jenkinsci.plugins.ghprb.GhprbBuildListener.onCompleted(GhprbBuildListener.java:12)
    at hudson.model.listeners.RunListener.fireCompleted(RunListener.java:201)
    at hudson.model.Run.execute(Run.java:1783)
    at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
    at hudson.model.ResourceController.execute(ResourceController.java:98)
    at hudson.model.Executor.run(Executor.java:410)

Test FAILed.