Fix command change_password (fixes #16)
Merge pull request #17 from scrogson/master

Binary conversions for mod_muc_admin
mod_admin_extra: for support in ejabberd-v13.x changed args from string to binary : all changes tested with ejabberdv13.12
Merge pull request #18 from rahulgautam/master

mod_admin_extra: for support in ejabberd-v13.x
Just return the value if it exists, otherwise return the default.

The guard here caused the ‘EXIT’ clause to be triggered in
`ejabberd_config:prepare_opt_val/4` on line 573 of
`ejabberd_config.erl`.
Clean up.
Add support for using yaml config file.

When converting to use the yaml config, the option for `allowed_ips`
gets stored as a binary. But needs to be compared against the client ip
of the request (which is a tuple). This converts the list of binaries
into a list of ip tuples.