synchronised reading of translations

[jtauber]

like we have in scaife.perseus.org but let's try to solve the problem of the corresponding text parts getting out of sync.

Also we don't currently serve up the English translations via any API.

Note also that there is some richer markup in at least one of the English translations than in the Greek.

[jacobwegner]

#25 will serve as the first implementation with GRC's alignment data delivered over the wire

[jacobwegner]

I think this is also largely going to be a front end task, so I've removed the backend label

[jtauber]

There may still be more backend stuff to do but we can always just create an issue elsewhere for that and reference it here.