Updated Sensor Type
Initialization of the Service Delivery & Utility manager core Module

Signed-off-by: Nikos Kefalakis <nkef@ait.edu.gr>
Updated SensorTypes.xsd and models
Updated SensorTypesPopulation.java
updated gitignore with .factorypath files
Converted openIotCommons to maven project

Signed-off-by: nkef <nkef@ait.edu.gr>
Updated Scheduler's and SD7UM's pom files
Merge branch 'ait-develop' into sensap-develop
Minor bug fixes
Redesigned the SPARQL code generator to generate nested queries

ToDo: Implement the generators for the non-date comparators