refactor: improve tree shaking abilities

Internal refactor completed in order to improve tree shaking and dead
code removal. The public API, with an exception to ion-slides, has
stayed the same. However, internally many changes were required so
bundlers could better exclude modules which should not be bundled.
Ultimately most changes resorted to removing references to `window` or
`document`, or a module that referenced one of those.

BREAKING CHANGES

ion-slides was refactored to remove the external dependencies, and
rewritten in TypeScript/ES6 modules to again improve tree shaking
abilities.

src/components/segment/segment.ts

@@ -195,7 +195,7 @@ export class Segment extends Ion {
   }
 
   /**
-   * @input {string} The mode to apply to this component.
+   * @input {string} The mode to apply to this component. Mode can be `ios`, `wp`, or `md`.
    */
   @Input()
   set mode(val: string) {