Add .travis.yml from affiliated package template

[cdeil]

I think getting continuous integration running on travis-ci will help ... I'd recommend adding this now and then switching on Python 3 tests, Sphinx docs build tests, ... as these things become available.

[cdeil]

@RayPlante Do you want this? Anything I should change?

[cdeil]

I've switched on Python 3 testing on travis-ci.

Locally I get an error:

$ python3.2 setup.py build
Traceback (most recent call last):
  File "setup.py", line 35, in <module>
    import pyvo
  File "/Users/deil/code/pyvo/pyvo/__init__.py", line 156, in <module>
    from . import registry
  File "/Users/deil/code/pyvo/pyvo/registry/__init__.py", line 8, in <module>
    from .vao import *
  File "/Users/deil/code/pyvo/pyvo/registry/vao.py", line 848
    delim = u"#"
               ^
SyntaxError: invalid syntax

But independently of this error I think you should switch on travis-ci testing ... testing every commit with Python 2 and 3 before merging prevents most regressions.

[cdeil]

travis-ci sees the same Python 3 issue:
https://travis-ci.org/cdeil/pyvo/jobs/11566014#L139