Also send PEP notifications when local contact updates CAPS

this fix mistake from previous commit 311fedaa

Either contributed module include dependencies this way
  deps/
    dep1/
      src/
      include/
    dep1/
      src/
      include/

Or includes rebar.config or rebar.config.script:
In this case, only git is supported (if git command available)
and ext_mod checkout code in deps directory.

In both case, only basic built procedure is supported. ext_mod
does not do more than bare compilation like this:
erlc -I include src/*erl

Let each plugin do its own initialisation in init_plugins
init_nodes was an old function to be removed.

PubSub: Check for node subscription of bare JID

XEP-0198: Increase default value of "max_ack_queue" option

New hook: muc_filter_packet

Let mod_pubsub send last items whenever a contact updates the entity
capabilities.  This was already done for remote contacts and is now also
done for local contacts.

The reason to use the caps_update hook for sending last items to remote
contacts is probably not obvious.

The function is call with binary format from ejabberd_c2s.

Give gen_fsm:sync_send_all_state_event/3 a little more time to transfer
the (possibly somewhat large) c2s #state during session resumption.

During login, clients might receive a relatively large number of stanzas
in one go.  For some users, the default value of the "max_ack_queue"
option turned out to be too small in that situation.

Add a hook that allows for modifying or dropping MUC room messages.

Closes #491.

We need MySQL 5.6 or newer in order to get support for InnoDB FULLTEXT
Indexes.

Closes #624.

Notify clients when the room configuration changes, as mandated by
XEP-0045, #10.2.1.

Closes #623.

configure.ac: add AC_CONFIG_MACRO_DIR

Otherwise, autoconf fails to find extra macros defined in the m4
directory.