This creates a new standalone build which should have everything the
default build has, plus a little extra. This is not a sustainable long
term solution (we shouldn't make people choose like this) but it fixes
the problem we have in the short term.
This also removes the terrible react-transitions build. This is better
anway.
Fixes#369
This builds `ReactTransitionGroup` with it's own copy of `React`, which
it total clownshoes. This should be technically usable, but definitely
should not be used in any production environment.
We're using populist for building the bundle of test modules and their
dependencies, so it seems worthwhile for consistency to do the same for
the test harness.