Merge 0.12->trunk

util.argparse: Revise 553c6204fe5b with a different approach The second return value is (not insensibly) assumed to be an error. Instead of returning a value there in the success case, copy the positional arguments into the existing opts table.

Merge 0.12->trunk

util.argparse: Return final 'arg' table with positional arguments for convenience This is the same as the input table (which is mutated during processing), but if that table was created on the fly, such as by packing `...` it's convenient if it also gets returned from the parse function.

mod_s2s: Improve robustness of outgoing s2s certificate verification This change ensures we have positively verified the certificates of the server we are connecting to before marking the session as authenticated. It protects against situations where the verify-or-close stage of the connection was interrupted (e.g. due to an uncaught error). Thanks to Zash for discovery and testing.

mod_s2s: Distinguish DANE TLSA errors from generic cert chain errors Otherwise it would just report "is not trusted" unless you inspect the logs. This message is sent to to the remote server, and will hopefully show up in their logs, allowing the admin to fix their DANE setup.

mod_s2s: Recognise and report errors with CA or intermediate certs Should be invoked for cases such as when the Let's Encrypt intermediate certificate expired not too long ago.

mod_smacks: Improve activation of smacks on outgoing s2s Using a timer was a hack to get around that stream features are not available at the right time and sendq stanzas were stored as strings so could not be counted properly. The later has now been fixed and the former is fixed by recording the relevant stream feature on the session so that the correct version of XEP-0198 can be activated once the connection has been authenticated and is ready to start.

util.crand: Reduce scope here too Same as previous commit

util.strbitop: Reduce scope of functions Equivalent to 'local' in Lua, these functions are exported via the luaopen_ function, which is the only one needing to be visible outside of the file. Pointed out by Link Mauve at some point, but there wasn't really any rush here.