Add 'clear' button

I found that, when watching the cells multiply, I often wanted to start
fresh but didn't want to click each of the new cells to toggle them off.
This button was easy to add and made it much easier to play with the UI.
Add cell count for each game listed in GameIndex

To further explore the way that Flux keeps everything in sync, I added a
count of cells to the listings in the GameIndex. It's neat to see them
live-update when you save a game with a new set of cells.

There is a bug where the cell count doesn't update when you only remove
cells. Looking into this next.
Fix bug where removed cells were not deleted on save

The server was returning the wrong data after 'save' because, even
though we did delete the old 'live' cells and make completely new ones,
the 'game' object was not reloaded and did not see the changes to it's
associated 'life' models.

We were also using the lodash deep 'merge' to combine the attributes
returned by the server with the previous attributes, when really we can
safely just overwrite the old attributes, trusting what the server
returns (now that it is correct).
Add ViewActionCreators for EcosystemGrid

Previously, the EcosystemGrid was directly calling the GameWebAPIUtils
to send updates to the server, which then triggered server actions. The
view didn't get updated until the server returned a response.

Adding a set of actions that trigger updates to the stores before
sending the update to the server will:
 * Optimistically update the UI and the data
 * Explore more uses of actions in the Flux architecture
Fix bug with updating of id on save