Add bloomfilter_clear() BiF.
Refactor Bloom filter merging.
Support emptiness check on Bloom filters.
Merge remote-tracking branch 'origin/topic/matthias/bloom-filter' into topic/robin/bloom-filter-merge

* origin/topic/matthias/bloom-filter:
  Support emptiness check on Bloom filters.
  Refactor Bloom filter merging.
  Add bloomfilter_clear() BiF.
Merge branch 'topic/robin/bloom-filter-merge'

* topic/robin/bloom-filter-merge: (50 commits)
  Support emptiness check on Bloom filters.
  Refactor Bloom filter merging.
  Add bloomfilter_clear() BiF.
  Updating NEWS.
  Broifying the code.
  Implement and test Bloom filter merging.
  Make hash functions equality comparable.
  Make counter vectors mergeable.
  Use half adder for bitwise addition and subtraction.
  Fix and test counting Bloom filter.
  Implement missing CounterVector functions.
  Tweak hasher interface.
  Add missing include for GCC.
  Fixing for unserializion error.
  Small fixes and style tweaks.
  Only serialize Bloom filter type if available.
  Create hash policies through factory.
  Remove lingering debug code.
  Factor implementation and change interface.
  Expose Bro's linear congruence PRNG as utility function.
  ...
Fixing random number generation so that it returns same numbers as
before.

That broke a lot of tests.
Updating tests.
Covenience make target to update the three coverage tests that usually
need tweaking when scripts get added/removed.
bif files declared with bif_target() are now automatically compiled
in.

No more manual includes to pull them in.

(It doesn't quite work fully automatically yet for some bifs that need
script-level types defined, like the input and logging frameworks.
They still do a manual "@load foo.bif" in their main.bro to get the
order right. It's a bit tricky to fix that and would probably need
splitting main.bro into two parts; not sure that's worth it.)
Merge branch 'master' into topic/robin/bloom-filter-merge
Fixing serialization bug introduced during earlier merge.
Merge branch 'topic/robin/bloom-filter-merge'

* topic/robin/bloom-filter-merge: (53 commits)
  Fixing serialization bug introduced during earlier merge.
  Updating tests.
  Fixing random number generation so that it returns same numbers as before.
  Support emptiness check on Bloom filters.
  Refactor Bloom filter merging.
  Add bloomfilter_clear() BiF.
  Updating NEWS.
  Broifying the code.
  Implement and test Bloom filter merging.
  Make hash functions equality comparable.
  Make counter vectors mergeable.
  Use half adder for bitwise addition and subtraction.
  Fix and test counting Bloom filter.
  Implement missing CounterVector functions.
  Tweak hasher interface.
  Add missing include for GCC.
  Fixing for unserializion error.
  Small fixes and style tweaks.
  Only serialize Bloom filter type if available.
  Create hash policies through factory.
  ...
Protection about broken traces with empty pcap headers.
Updating submodule(s).

 [nomail]
Merge remote-tracking branch 'origin/master' into topic/bernhard/hyperloglog

Conflicts:
	src/Func.cc
	src/probabilistic/CMakeLists.txt