Made the fetching functions a little less brittle and updated some of the hydrograph rendering tests.

how to bring in a non-ES6 module or figure out how to import Leaflet.

Initial refactoring. For the most part this was renaming functions and moving things around. Have not tried to run anything.

Created a monitoring-location directory. Javascript that is unique to storing data and rendering that page was moved to this directory. This follows the same pattern as the networks directory.

Update to use d3-redux library which no longer stores the store on the d3 node. Instead the store is provided explictly when needed to dispatch actions or when selectors are used.

Refactored the last test suite as each suite should only have one beforeEach. Also eliminated one of the tests since it wasn't really testing anything.

Added test for legendDisplaySelector that it returns the correct mask values based on the currentVariableID.

Hide y-axes on screens less than $site-max-width in USWDS; make margins a function of browser width; add a mediaQuery to utils, to mimick USWDS's media mixin in Javascript; wrap tooltip text when it exceeds the available space.