delete empty test files

tasx-6
add javadocs to taglib

tasx-6
move task serializer from service to domain class

tasx-23
define date format in configuration file

tasx-23
Merge branch 'feature/tasx-6-task-view-controller' into feature/tasx-21-ui
Merge branch 'feature/tasx-23-task-rest-api' into feature/tasx-21-ui