Make colorize-svg.js actually work more often
Make colorize-svg.js actually work more often

Follow-up to e4358fdba586dd6266e1c800a71375614c7510fa.

We allow the following formats:

* { "file": "foo.svg" }
* { "file": { default: "foo.svg" } }
* { "file": { ltr: "foo.svg", rtl: "foo.svg" } }

But the second didn't work at all.

Also simplified how we handle images without LTR/RTL variants.

Change-Id: I00e992ec692957a60d4e23a427774251903457f8

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui