Update BloomFilter

Allow the user to configure the number of hash functions as well as add
support for serializing/deserializing the bloom filter from a stream.
Add a hashCode to the bloom filter.
Don't take static memory of test base classes into account when checking for static leftovers.
Added catch EsRejectedExecutionException when trying to reschedule river start
Added test for Update API via native scripts

Motivation was to have a test ready as well as something other people could have a look at.
Size docIdsToLoad appropriately in SearchService

Closes #4156
Added test for PR #4157 (deep pagination in a small index)
Handle pretty=false and missing line feed for pretty=true which is the default for main REST action