Add the LAST function to the Java parser and its associated classes.
It will save the last value received by its timestamp
Update SubAlarmDb to have a state field. This will be used in the
Threshold Engine for the new LAST function
Add a force argument to SubAlarmStats.addValue() because the
Threshold Engine will always need to add the values for the alarm
because they are only sent once
The changes to Java Monasca API and Monasca Thresh for this last-value
will require these changes, first
Also, remove all trailing spaces from AlarmExpression.g4
Change-Id: Ie3192370057676e89bfebbc5ce4243b1a3ecf0ea
Implements: Blueprint last-value
6a67fecc80