Added module def_MailingListManagerEmail for creating of new mailing list
Added getAttributeDefinition into module def_MailingListManagerEmail
Merge pull request #25 from papperwing/Mailing_list_manager_email

Attribute for mailing list manager email
Added possibility to change perun's configuration files location on build or runtime.

 - added variable ${perun.conf.custom} which is not used by maven (but can be)
 - running jar/war with -Dperun.conf.custom=/home/user_name/.perunv3 will override default config from /etc/perunv3
 - changed way of wiring property file in perun-registrar
 - added definition of coreProperties to perun-core (not yet used to loading properties)