Incorporate astropy package-template

[keflavich]

Astropy's package-template includes a suite of tools for testing, installation, and documentation building. The documentation building may conflict with the current setup, I'm not sure, but the installation should be only a plus.

It would be nice to put vamdclib on pypi, which this PR can facilitate

[bsipocz]

Is there any timeline on this and a possible release? It would be nice to not ask users of astroquery to install from a fork but to use a released version.

[bsipocz]

@keflavich - I'm unable to install your fork following the docs we provide:

pip install https://github.com/keflavich/vamdclib/archive/master.zip
WARNING: pip is being invoked by an old script wrapper. This will fail in a future version of pip.
Please see https://github.com/pypa/pip/issues/5599 for advice on fixing the underlying issue.
To avoid this problem you can invoke Python with '-m pip' instead of running pip directly.
Collecting https://github.com/keflavich/vamdclib/archive/master.zip
  Using cached https://github.com/keflavich/vamdclib/archive/master.zip
    ERROR: Command errored out with exit status 1:
     command: /usr/local/opt/[email protected]/bin/python3.9 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/dc/hsm7tqpx2d57n7vb3k1l81xw0000gq/T/pip-req-build-8x4746s2/setup.py'"'"'; __file__='"'"'/private/var/folders/dc/hsm7tqpx2d57n7vb3k1l81xw0000gq/T/pip-req-build-8x4746s2/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /private/var/folders/dc/hsm7tqpx2d57n7vb3k1l81xw0000gq/T/pip-pip-egg-info-1c_z224u
         cwd: /private/var/folders/dc/hsm7tqpx2d57n7vb3k1l81xw0000gq/T/pip-req-build-8x4746s2/
    Complete output (9 lines):
    The requested path 'astropy_helpers' for importing astropy_helpers does not exist, or does not contain a copy of the astropy_helpers package.
    Downloading 'astropy-helpers'; run setup.py with the --offline option to force offline installation.
    No source found for the 'astropy_helpers' package; astropy_helpers must be available and importable as a prerequisite to building or installing this package.
    
    If the problem persists consider installing astropy_helpers manually using pip
    (`pip install astropy_helpers`) or by manually downloading the source archive,
    extracting it, and installing by running `python setup.py install` from the
    root of the extracted source code.
    
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

[bsipocz]

Using this branch I run into this error with astroquery, it maybe related to those last two commits? For some weird reasons I don't see them when I clone your fork... :

________________________________ ERROR collecting astroquery/vamdc/tests/test_vamdc.py _________________________________
/usr/local/lib/python3.9/site-packages/pytest_doctestplus/plugin.py:184: in collect
    module = self.fspath.pyimport()
/usr/local/lib/python3.9/site-packages/py/_path/local.py:704: in pyimport
    __import__(modname)
astroquery/vamdc/__init__.py:22: in <module>
    from .core import VamdcClass
astroquery/vamdc/core.py:110: in <module>
    Vamdc = VamdcClass()
astroquery/vamdc/core.py:38: in __init__
    self._nl = vnodes.Nodelist()
/usr/local/lib/python3.9/site-packages/vamdclib/nodes.py:29: in __init__
    self.nodes.append(Node(node['name'], url=node['url'], referenceUrl=node['referenceUrl'],identifier = node['identifier'], maintainer=node['maintainer'], returnables=node['returnables']))
E   KeyError: 'referenceUrl'
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