Implement "event" evaluation strategy for "variable" granularity

[sarusso]

Follows fixing #63

Granularity variable:

GT var1)        = 
MO var1) 
GT var2)   
MO var2)
tp: 0/1
fp: 0

GT var1)        = 
MO var1)        =
GT var2)   
MO var2)
tp: 1/1
fp: 0

GT var1)        = 
MO var1)        =
GT var2)   
MO var2)      =
tp: 1/1
fp: 1


GT var1)        = 
MO var1)       
GT var2)   
MO var2)      =
tp: 0/1
fp: 1

GT var1)       =========
MO var1)         =======
GT var2)   
MO var2)    ========
tp: 1/1
fp: 1

GT var1)       =========
MO var1)         =======
GT var2)   
MO var2)
tp: 1/1
fp: 0