[TASK] Added phpunit to dev dependencies
updated composer.json
[TASK] Merged c97ff38d from SagaConsultingGroup as this fixes
wrong nested tags for Issuer and batchBooking
added checks for empty BIC in CdtrAgt
[TASK] Merged optional BIC and improved test
Different scenarios for the validation are still missing
adjustable format for creation date time

A local time format with utc offset ("'Y-m-d\TH:i:s.000P")
is required by a german bank (sparkasse-koelnbonn.de).
Added code documentation for the unique message identification parameter
Fix pain.008.001.02 for Spanish banks

Fix header for Spanish banks, see https://github.com/digitick/php-sepa-xml/issues/44
Shema,xml and Test for pain.008.003.02 added
BIC now only Optional
added test for single transaction without BIC
[TASK] Renamed test to match convention
[TASK] Updated travis build state image path
[TASK] Fixed travis link
Allow setting an optional EndToEndId

With this change it is possible to specify an explicit EndToEndId. The
change does not interfere with existing implementations.
[TASK] Changed the order for creating the timestamp

This should prevent runtime issues when the test is executed
[TASK] Fixed travis build state
Fixed: Custom EndToEndId in DirectDebits