Add CF convention metadata to variables

[jmcvey3]

PR to add metadata to dolfyn-created variables. Update for #102

[coveralls]

Pull Request Test Coverage Report for Build 4059134169

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 192 of 203 (94.58%) changed or added relevant lines in 16 files are covered.
• 214 unchanged lines in 11 files lost coverage.
• Overall coverage decreased (-0.01%) to 89.906%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
dolfyn/adv/motion.py	5	6	83.33%
dolfyn/io/nortek2_defs.py	35	36	97.22%
dolfyn/io/rdi.py	11	12	91.67%
dolfyn/adv/turbulence.py	9	11	81.82%
dolfyn/io/api.py	14	16	87.5%
dolfyn/io/nortek.py	23	27	85.19%

Files with Coverage Reduction	New Missed Lines	%
dolfyn/io/base.py	2	93.13%
dolfyn/rotate/rdi.py	2	96.83%
dolfyn/adv/turbulence.py	3	94.87%
dolfyn/velocity.py	4	93.98%
dolfyn/adp/clean.py	5	94.87%
dolfyn/io/nortek2_defs.py	6	95.93%
dolfyn/rotate/base.py	8	92.08%
dolfyn/rotate/vector.py	11	90.68%
dolfyn/io/nortek2.py	19	91.57%
dolfyn/io/nortek.py	46	90.25%

Totals
Change from base Build 4008776229:	-0.01%
Covered Lines:	5077
Relevant Lines:	5647

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💛 - Coveralls