This also updates all usages of the deprecated Val ctor to use
either IntervalVal, TimeVal, or DoubleVal ctors. The reason for
doing away with the old constructor is that using it with TYPE_INTERVAL
isn't strictly correct since there exists a more specific subclass,
IntervalVal, with overriden ValDescribe() method that ought to be used
to print such values in a more descriptive way.
Due to string representation of Broker vectors changing (they now
use parentheses instead of square brackets).
Related to https://github.com/zeek/broker/issues/43
This test-case has actually revealed an interesting issue - it works as
is, but as soon as one adds a vector, one gets the fun error-message
fatal error in any: BroType::AsVectorType (any/vector) (any)
This will require a bit more digging :).
