Random team generation scripts are no longer in scripts.js, but instead
in a new file random-teams.js.
The scripts are now also no longer run from inside battles, but in a
new team generator object. This makes it easier for external scripts
to generate random teams by running Dex.generateTeam(format).
This makes gen 7 the default mod, updates the tests to match, and fixes
the corresponding build error.
Note that this only changes the default Tools mod, the default Formats
mod is now gen6. gen7 must be specified by name in a format, for that
format to be a gen 7 format.