data.js: tag each verb as 'verb'
main.js: remove stray console.log()
main.js: consider tags in translation problems

When generating translation problems, only consider alternatives that
have the same set of tags to make it harder.

It doesn't make much sense to mix ordinal numbers and verbs in the same
problem as it makes it too easy.
data.js: tag each ordinal number as 'ordinal'

Make it possible to distinguish ordinal numbers from other words by
tagging them as 'ordinal'.  Ordinal numbers are '1st, 2nd, 3rd, ...' as
opposed to '1, 2, 3, ...'.
data.js: delete female and neuter words for now

We can automatically generate the female and neuter variants of most
words using simple rules.  Remove them from the manually-entered data
for now, less lines means less work.
data.js: prepare for gender-based list expansion

Make it possible to auto-expand the list of translations by marking
masculine words that can be auto-expanded as 'gender-expand' and
'masculine'.

Remove the masculine marker '(m)' marker from expandable words so
it's easier to add the female and neuter variants.