Log Message:
Update chat/ejabberd to 16.01

Security
- Improve Dialback Key Generation and Validation support (XEP-0185)
- More generally, improve random number generator to avoid timing /
  guessing attacks on any random value.

Database
- Use BLOB instead of TEXT on mysql in stanza storage
- Use UTF8MB4 character set in MySQL tables
- Make Riak working on Erlang R18

MAM
- Use stanza-id tags for deduplication
- Advertise MAM in disco info for account/room JID
- Improve MUC support
- Don't store resent messages
- Do not forget to include xmlns in mam prefs response (#859)
- Honor Message Processing Hints (XEP-0334)

MUC
- Add support for muc#roomconfig_presencebroadcast option
- Only filter rooms in Service Disco when more than 100 (EJAB-343)
- List in Service Disco non-empty rooms and provide Node for empty (EJAB-343)
- When user joins logged room, he must be warned (EJAB-726)

Pubsub
- Fix pubsub virtual nodetree plugin
- Use correct notification_type for last items (#827)
- PubSub plugin for online users only
- Disable use of multi-subscribe and subscription-option on standard
  plugins
- Limit number of subscriptions per node and allow custom default node
  configuration
- Don't force max_items_node to MAXITEMS if not defined
- Don't read pubsub options when plugin does not use them

Elixir
- Upgrade Elixir to v1.1.0

Admin
- Add plugin for passing extra erl_opts flags to deps, and use it
  for hipe
- Add --enable-latest-deps to configure
- Remove "--enable-nif" flag
- New send_stanza command
- ejabberdctl: new --no-timout flag
- ejabberdctl: Don't let "reopen_log" rotate files (EJAB-1243)
- ejabberdctl: Improve escaping of arguments passed to ejabberdctl
- OpenSSL minimum required version: raised from 0.9.8 to 1.0.0

Config
- New option accept_interval in ejabberd_listener
- Webadmin console visual refresh (EJAB-1142)
- If mod_register access_from is 'none', then don't advertise IBR (#857)
- Fix handling of some options in old style configs
- Fix parsing option trusted_proxies
- Fix ipv6 configuration processing (#803)
- ejabberd_service: simplify configuration: no need for 'hosts', just
  provide 'password'

Cleanup and optimisations
- Faster string_to_jid/1 implementation
- Move JID related functions from jlib.erl to jid.erl (#847)
- Remove usage of erlang's now()
- Update dependency name from p1_cache_tab to cache_tab
- Use crypto:rand_uniform instead of random:uniform
- Fix randoms.erl on R17 that don't have random:seed(integer())
- Faster and more memory efficient XML parsing.
- Faster stringprep library.

Other changes
- ejabberd_http: Cope with large POST/PUT requests
- ejabberd_http: Log debug message on receive errors
- mod_offline: Discard chat states notifications
- mod_offline: Honor store hint
- mod_http_upload: various fixes
- XEP-0198: Fix stanza counting corner case issue
- Adding WEBIRC, custom realname & ident, ISO-8859-15
- Update hebrew translation