Sdss-access

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- Feature - Adds new functions for mwm `healpixgrp`, `apginst`, and `apgprefix` to determine other keywords from existing `telescope` kwarg
- Support :issue:`25` - Adds ``preserve_envvars`` option to preserve original os environment variables

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- Feature :issue:`7` - Adds a progress bar to downloads with `tqdm`
- Feature :issue:`18` - Allow Path to work off of loaded module files
- Bug Fix: issue appending compression suffixes when wildcards present

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- Bug Fix :issue:`16` - HttpAccess used in public mode checks for netrc file
- Combines separate `set_auth` methods in `BaseAccess` and `HttpAccess` into a single `set_auth` available as `AuthMixin`
- `Auth.set_netrc` now raises an `AccessError` on failure to find a value netrc file.

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Refactored
^^^^^^^^^^
- Modified sdss_access to use the new versioned tree. Removes input and dependency on single `sdss_paths.ini` file.
- sdss_access no longer uses ConfigParser to parse the `sdss_paths.ini` file
- path templates are passed in directly from the `tree` python product
- The symbol for "special function" path definition has changed from `%` to ``
- `sdss_access` now checks for compressed/uncompressed files on disk compared to its path template definition
- remote access classes, i.e `RsyncAaccess`, no longer need both public and release to be specified to access DRs. Sets public=True automatically if `DR` in release name.
- Added ``path.changelog`` module with new ``compute_changelog`` and ``get_path_templates`` functions to compute changes in paths between releases
- Moved tests out of ``sdss_access`` python package to top level.
- Deprecated included logger and config in favor of ``sdsstools`` logger and config.
- Simplified python package setup.cfg and consolidated requirements files

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- Pinning sdss-tree requirement to <3.0

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Fixed
^^^^^
- Bug in remote file existence check for following redirects.