Updated cleaning methods

[aburrell]

Description

When looking at coveralls, I discovered that the clean routines contained logic for 'none'. Since clean is not called with this input, I decided to remove it. I also:

• moved a no-cleaning warning in JRO ISR to preprocess so that it will be accessible
• Updated the clean docstrings

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

import pysat
import pysatMadrigal as py_mad

jro = pysat.Instrument(inst_module=py_mad.instruments.jro_isr, tag='drifts', clean_level='none')
jro.load(2014, 20)

pysat WARNING: unknown data variable(s) ['vipn' 'dvipn' 'vipe' 'dvipe' 'vi7' 'dvi7' 'vi8' 'dvi8'], using only: ['nwlos' 'range' 'vipn2' 'dvipn2' 'vipe1' 'dvipe1' 'vi72' 'dvi72' 'vi82'
 'dvi82' 'paiwl' 'pacwl' 'pbiwl' 'pbcwl' 'pciel' 'pccel' 'pdiel' 'pdcel'
 'jro10' 'jro11']
WARNING:pysat:unknown data variable(s) ['vipn' 'dvipn' 'vipe' 'dvipe' 'vi7' 'dvi7' 'vi8' 'dvi8'], using only: ['nwlos' 'range' 'vipn2' 'dvipn2' 'vipe1' 'dvipe1' 'vi72' 'dvi72' 'vi82'
 'dvi82' 'paiwl' 'pacwl' 'pbiwl' 'pbcwl' 'pciel' 'pccel' 'pdiel' 'pdcel'
 'jro10' 'jro11']
<ipython-input-10-027e4e553f7c>:1: UserWarning: Metadata set to defaults, as they were missing in the Instrument
  jro.load(2014, 20)
pysat WARNING: interpretation of drifts below 200 km should always be done in partnership with the contact people
WARNING:pysat:interpretation of drifts below 200 km should always be done in partnership with the contact people

Test Configuration

• Operating system: OS X Mojave
• Version number: Python 3.8
• Any details about your local setup that are relevant: develop branch of pysat

Checklist:

• [x] Make sure you are merging into the develop (not main) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have linted the files updated in this pull request
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to CHANGELOG.md, summarizing the changes

If this is a release PR, replace the first item of the above checklist with the release checklist on the pysat wiki: https://github.com/pysat/pysat/wiki/Checklist-for-Release

[aburrell]

@jklenzing curious if you have any ideas about the best way to test for the no cleaning warning in preprocess for JRO.