This change converts our API methods to TypeScript. Our apiUtils file

has a few methods, primary among them being apiCall. This change adds

typing for everything, and cleans up some old cruft. It does not yet

make any changes to the internals of how API requests work.
In order to facilitate using jasmine for unit tests. these methods are

all exported under a new top-level object called API.

Ran js-tests.
Smoke tested the UI and verified that things still worked correctly.