Implement new object-model specification

 * Implemented new object model
 * Implemented spec validation
 * Old DSL parser was deleted
 * All code is replaced by new workbook spec
 * Also tests are fixed
 * events -> triggers
 * Unit tests

Implements: blueprint mistral-dsl-model
Partially implements: blueprint mistral-dsl-validation
Partially implements: blueprint mistral-rename-event-to-trigger

Change-Id: I782b7983ddc724375229587f467c55ad9341478b