sh -c
make NSUPDATE_SERVER can be overwritten
fix https://github.com/Neilpang/acme.sh/issues/2134
fix https://github.com/Neilpang/acme.sh/issues/2052
fix https://github.com/Neilpang/acme.sh/issues/2037
https://github.com/Neilpang/acme.sh/issues/2037
https://github.com/Neilpang/acme.sh/issues/2005
buypass support 180 days.
1. fix https://github.com/Neilpang/acme.sh/issues/1977 2. The cache is too long to as a line to save in the conf
https://github.com/Neilpang/acme.sh/issues/1932
cache dns zones response