Generate valid mix10 and mix20 metadata (various values are Rational).

[tledoux]

The Brightness, ApertureBias and FlashEnergy properties are now Rational as needed for the versions 1.0 and 2.0 of the MIX schema.
Add unit test for all the new outputs.
Should also correct #387 : need for a sample file.

[codecov]

Codecov Report

Merging #394 into integration will increase coverage by 0.83%.
The diff coverage is 69.09%.

@@                Coverage Diff                @@
##             integration     #394      +/-   ##
=================================================
+ Coverage          48.99%   49.82%   +0.83%     
- Complexity           955      976      +21     
=================================================
  Files                 55       55              
  Lines               7626     7631       +5     
  Branches            1378     1378              
=================================================
+ Hits                3736     3802      +66     
+ Misses              3412     3370      -42     
+ Partials             478      459      -19

Impacted Files	Coverage Δ	Complexity Δ
...edu/harvard/hul/ois/jhove/handler/TextHandler.java	0.54% <0%> (-0.01%)	2 <0> (ø)
.../edu/harvard/hul/ois/jhove/handler/XmlHandler.java	63.07% <100%> (+2.11%)	274 <0> (+19)	⬆️
...a/edu/harvard/hul/ois/jhove/NisoImageMetadata.java	74.64% <100%> (+0.86%)	175 <0> (+2)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1e10d89...1edea28. Read the comment docs.

[carlwilson]

Nice, thanks for the tests :)