OTP 21 integration

[sebastiw]

Solves #199

[benoitc]

cc @etrepum thoughts?

[etrepum]

My primary concern is just backwards compatibility. If this requires changes to usage we’re going to need to document it well. Maybe have a deprecation period?

Haven’t had the time to go through and audit it myself yet.

[etrepum]

I’m away all week and probably won’t have a chance, if someone else looks into this we could get it merged more quickly.

[benoitc]

@sebastiw why templates are move to support? Maybe this could be made as a separate issue to focus on Erlang 21?

[sebastiw]

the whole support-dir is moved to priv/ because of ssl_cert_opts/0 and the use of code:priv_dir/1

https://github.com/mochi/mochiweb/pull/201/files#diff-a8c3e747ab3f8a14dc6605125a437097R7

[sebastiw]

but yeah, the useage of that is only within testing.

[etrepum]

I'm going to close this PR as we have other more minimal PRs that provide OTP 21 compatibility. It looks like there may be some future improvements we can make, but I would prefer to have each in separate PRs to make it easier to test and review.