Accepting PR for copy on size match? (#133 #183 #212)

[mbforbes]

Hey Zach,

I took a stab at implementing a feature I've wanted for a long time: directly copying the image when a width matches. This:

• cut my build times by about ~50% (23mins to 12mins)
• avoids double-compressing images
• keeps file sizes smaller
• is opt-in, behind an optional flag

Would you like a PR for this? If so I'm happy to clean it up and send over.

Related:

• issues: Skip image processing with eleventy-img - raw image? #133 Possible to copy image (passthrough) rather than reprocess? #183 Feature request: Add width/height attributes only #212
• the patch: mbforbes@f751202#diff-ad20a1a6b0c6cdb94f5aa0f680475c5d5f3f1b163b19be745fe52b6db38ad056
• on npm as https://www.npmjs.com/package/@mbforbes/eleventy-img/v/7.0.0-gamma.1