Summary:
This adds support for greek times.
There are still some issues with expressions of the form:
```
9:30 - 11:00 την πέμπτη
```
Where `11:00 την πέμπτη` is parsed first (as 11:30 on Thu), instead of prioritizing `9:30 - 11:00` as the training data suggests. These tests are for the moment excluded from the corpus.
Reviewed By: patapizza
Differential Revision: D6376271
fbshipit-source-id: 2f31e058fb88386429070e3b51cd33f93b9c5936