* Fix AWG<-> mm2 conversions
Add an inverted dictionary and a lookup function from awg -> mm2. Also
do some minor refactoring. Both sides of the conversion table were
converted to strings, since '0000' and '2/0' are perfectly valid AWG
values.
* Update example ex02 with awg -> mm2 conversion
Show conversions for ex02, and make sure it displays conversions in both
directions. Rebuild the example files.
* Fix faulty conversion of non-(mm2,AWG) units
The parsing allows arbitrary units to be used for cable dimensions --
this might be valid units, e.g. square inches, or invalid, e.g. bananas.
We only allow conversion between mm2 and AWG, so check that the
gauge_unit is either of those before conversion. If not, pass through as
is.
* Fix AWG string casing in output
Convert e.g. 'awg, 'AwG' to upper case for consistent rendering. Leave
any other input gauge units as they were.
Co-authored-by: Daniel Rojas <github@danielrojas.net>
