escaped HTML entities like > were unescaped in the final mjml output

[FelixSchwarz]

Fixes #52

@sh-at-cs, @caseyjhol: In the end I went for a really narrow unescaping implementation. By doing so I hope that there are fewer potential security issues (who knows what obscure features CSS has/will get?). Do you think that this minimal implementation is good as well?

[caseyjhol]

Nice! I think this is a good solution. Thanks for the quick turnaround, and apologies for overlooking this in the first place.

[caseyjhol]

Do we want to consider releasing this as a patch instead of a minor release?

[FelixSchwarz]

apologies for overlooking this in the first place.

No worries, I did the same mistake back then.

Do we want to consider releasing this as a patch instead of a minor release?

I think this is a pretty security major issue given the possibility that untrusted users might heavily rewrite the structure of emails sent through a web platform. Therefore I'd prefer putting this out as a "minor" release.