Conversions: moving triggers to "any"
Conversions: Fixing bug and simplifying parsing
Conversions: Switching to named matches
Conversions: Adding support for how many <units> in <quantity> of <other_units>?
Conversions: Adding failing tests for 'how many pounds in kilogram'
Conversions: naming more regex components
Conversions: supporting "how many <unit> in <unit>"
Conversions: Adding support for a and an in 'how many cm in an inch?' and 'how many cm in a metre?'
Conversions.t: organize into sections.

As the breadth and depth have increased here, it can be difficult to know
where to add new regression tests.  Hopefully this makes it easier.

Also convert '-ANY-' for HTML checking to make it more clear that we are
intentionally not checking.
Conversions.pm: remove unused module.
Conversions: allow articles to imply 1 on source units.

Thanks to @mintsoft for making this so easy to accomplish!
Conversions: try to use plural context to pick implicit 1.

We should not flip when the second unit is plural, since we can infer
the 1 on the other unit.  The "two plurals with not numbers" case is
now unflipped, but this was always ambiguous, so I don't think this is
worse than before.