get_coord to allow non-array

[d-chambers]

Description

This PR fixes an issue in which get_coord would fail if a list was passed as the values argument (rather than an array).

Checklist

I have (if applicable):

• referenced the GitHub issue this PR closes.
• documented the new feature with docstrings or appropriate doc page.
• included a test. See testing guidelines.
• your name has been added to the contributors page (docs/contributors.md).
• added the "ready_for_review" tag once the PR is ready to be reviewed.

[codecov]

Codecov Report

Merging #240 (237348c) into master (ad0f974) will increase coverage by 0.11%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #240      +/-   ##
==========================================
+ Coverage   98.90%   99.01%   +0.11%     
==========================================
  Files          76       76              
  Lines        6275     6280       +5     
==========================================
+ Hits         6206     6218      +12     
+ Misses         69       62       -7     

Flag	Coverage Δ
unittests	99.01% <100.00%> (+0.11%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
dascore/proc/rolling.py	100.00% <ø> (ø)
dascore/utils/hdf5.py	95.40% <ø> (+2.04%)	⬆️
dascore/core/coords.py	100.00% <100.00%> (ø)
dascore/io/indexer.py	97.54% <100.00%> (+2.12%)	⬆️
dascore/utils/time.py	100.00% <100.00%> (ø)

[d-chambers]

This fixes some, but not all, of the issues related to LF das processing. I am going to merge for now, then circle back to tackle the rest and #242 in the next few days. We will want to wait until those are all resolved before doing the 0.0.13 release, but it is long overdue! Early next week is a reasonable target.