Prepare ChurchDB for i18n and fix some minor bugs
(CS) Bugfix email send to person
Bugfix creating i18n for churchore
(CS) Optimize Song look&feel
(CS) Next step for integrate agenda
Fixed source preparation script to support whitespaces in the directory names.
Remove mysqli use

This replaces mysqli use with PDO hardcoded to mysql.
Start using composer for external dependencies

It's more comfortable than managing versions and updates by hand...