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.