Add owa wowa

See merge request !15

# Conflicts:
#   server/src/main/java/be/cylab/mark/datastore/RequestHandler.java

Updated the ActivationController to hold information of when is the last time an agent was triggered and check if enough time has passed to trigger it again depending on the Detection Agents trigger_interval parameter. Added accordingly UnitTests to test these functionalities

Added a field "trigger_interval" to the DetectionAgentProfile which will be used to signal at what intervals the detection agent should be triggered

Updated how the size of the DBs are shown on the Status page o the UI (now correctly shows the size in MB)

Changed that the uniqueSubject count is retrieved from the Collection_DATa instead of Collection_EVidence; This is already the case on the trunk, for some reason the change wasn't present on this branch

Removed the try-catch and instead changed the scale of the db size field. From scale 1 to scale 1024 (retrieve the size data in KB instead of B)

Added a try-catch clause for extractInt when the field is of form Long instead of Int. If an error occurs it is logged to the LOGGER too

Added a try-catch clause when trying to get the status of the database as when the size of a collection exceeds 2^31-1 (max integer value) it returns instead a double, which can cause an error

Added style changes where needed - added Override notation to couple of the methods and added method comments to others where missing

Added extra comments to the OWAverage detection aggregation agent. Extended the OWAverageIT test to check how the scores are aggregated for less scores than weights and more scores than weights