Moving all `math.js` definitions into a single JSON array, complete with i18n syntax for all messages, dropdowns, and tooltips.
Adding Blockly.Extensions.buildTooltipForDropdown(..) to facilitate the creation and error-checking of tooltips that update based on the value of a dropdown.
Now warn on raw string in JSON 'extensions'.
Replaces old colour block definitions with a Blockly.defineBlocksWithJsonArray(..) call. Generator unit tests continue to load and pass, signifying compatibility with prior block definitions.
Replaces extension 'math_number_tooltip' with the reusable 'parent_tooltip_when_inline' extension, also used by colour_picker. Includes tests.
