In Worldwind, Point.iconURI primitive should support base64 images

[sjpinizzotto]

This is to make line editors work. The vertices will be base 64 images.

[jaybarra]

Test Branch

feature/emp3-web#84-ww-base64-icon

Test values

• url - https://upload.wikimedia.org/wikipedia/commons/e/e0/Globcal_medium_resolution_globe.png
• base64 data (16x16 red square) data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAHklEQVQ4T2P8z8Dwn4ECwDhqAMNoGDCMhgHDsAgDAKXUH/HLXNS/AAAAAElFTkSuQmCC

Use other values as necessary

[jamesbeecroft]

Reintegrate