Implement Multiple Change Impact Mode into the GA Client

[DJSekora]

Multiple Change Impact Mode (name tentative) is a mode that will work similarly to Single Change Impact Mode, except the compared origin sets can vary at any number of points instead of just one addition. The idea is that the user can, upon switching to MCI mode, upload a second latlong file of origin points, which will be compared in the same manner as the sets in Single Change Impact Mode.

To add this mode, the following changes need to be implemented:

1. Add a button to the GA index.html that allows the user to upload a second file of latlongs (it can be placed right next to the first upload button).
2. Add handling in the GA client.js that hides the second file upload button if the mode is not Multiple Change Impact (this should be simple - in the Analyst Client, an entire section of the options pane is hidden at times).
3. Figure out the best way to send a second set of origin coordinates from the GA client.js (may require the creation of new routing parameters, like FromPlace2 and ToPlace2; this will in turn require you to add these parameters to RoutingResource.java and possibly several other places, and also to handle them in TileService.java).
4. Add appropriate handling in Renderer.java for the Multiple Change Impact Mode (the layer enum to use here is called CLOSECOMPMULTIPLE).
5. Uncomment the Multiple Change Impact Mode in the GA index.html