mvn new SNAPSHOT version

[aanno]

Derived from #185: New mvn SNAPSHOT version for master branch

[v-jizhang]

Hi @aanno
The following test freezes on linux platform, please take a look. in nailgun directory, do

$ export PYTHONPATH=.
$ python nailgun-client/py/test_ng.py
Traceback (most recent call last):
  File "nailgun-client/py/test_ng.py", line 353, in <module>
    was_successful = unittest.main(exit=False).result.wasSuccessful()
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/main.py", line 95, in __init__
    self.runTests()
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/main.py", line 256, in runTests
    self.result = testRunner.run(self.test)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/runner.py", line 176, in run
    test(result)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/suite.py", line 84, in __call__
    return self.run(*args, **kwds)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/suite.py", line 122, in run
    test(result)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/suite.py", line 84, in __call__
    return self.run(*args, **kwds)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/suite.py", line 122, in run
    test(result)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/case.py", line 653, in __call__
    return self.run(*args, **kwds)
  File "/opt/circleci/.pyenv/versions/3.6.2/lib/python3.6/unittest/case.py", line 601, in run
    self.setUp()
  File "nailgun-client/py/test_ng.py", line 67, in setUp
    self.startNailgun()
  File "nailgun-client/py/test_ng.py", line 154, in startNailgun
    the_first_line = str(self.ng_server_process.stdout.readline().strip())
KeyboardInterrupt