Optimize all SVGs

Passed with svgo 0.4.2 <https://github.com/svg/svgo>, then prepended
'<?xml version="1.0" encoding="UTF-8"?>' prolog to each file since
svgo sees it fit to remove it and that breaks file type detection.
svgo truncated all numerical values to a maximum of 3 decimal places
of precision.

tick.svg: Removed leftover no-op styling left after text was
converted to path.

ime-active.svg: Reused remove-input.svg from ULS MediaWiki extension
with different scaling.

Image       Orig     New
ime-active  6664    2133
tick        2331     247
Merge pull request #327 from Nikerabbit/svgo

Optimize all SVGs