Add HTML compression back to v1

[JanStevens]

Hello,

Why did version 1.0.0 remove the html compressor?
We have a lot of templates and our JS became noticeably bigger

[pitr]

I removed html compressor during Sprocket 3 upgrade (#126) because there were no tests for it. Feel free to add it back, but please add tests so the feature does not break in the future.