Throw error when instantiating unrecognized charts

This explicit error is more instructive than what is currently being
thrown in this case:

    Uncaught TypeError: Cannot read property 'prototype' of undefined
Implement support for Internet Explorer

Ensure that the library and its tests are compatable with IE8 (provided
the d3.js-endorsed "aight.js" library is present), IE9, and IE10.
Release v0.1.2