TS/JPM: printing number of deletes encountered + 'continueAfter'
TS/JPM: work in progress: testing and optimizing performance for SequentialStorage
TS/JPM: more defensive close (can be called more than once, even if not initialized properly)
TS/JPM: closes Index on KeyboardInterrupt (for diagnostic purposes)
TS/JPM: proper signal handling that ensures flushing of index on SIGINT or SIGTERM
TS/JPM: simplified and fixed SeqStoreSortingCollector
JPM: just moved performance 'test' out of the way
JPM: potential optimization in SeqStoreSortingCollector (test/probe/profile better at some other time)
JPM: new Java class to be used in SequentialStorage._Index
JPM: SequentialStorage now works with SeqStorageIndex.java
JPM: cleaned up sequentialstorage.py
JPM: further optimization of itervalues with Collector (before starting on another approach that doesn't require slow NumericRangeQuery)
TS/JPM: added SequentialStorageTest.testKeyErrorForUnknownKey
TS/JPM: work in progress: delegating itervalues() to Java with termsEnum
JPM/TS: added test using _Index.itervalues() after a delete.
JPM/TS: fixed more code, most tests work, work in progress.
JPM/TS: simplified SeqStorageIndex.java, added NumericUtils.filterPrefixCodedLongs to wrap termsEnum.
EG/JPM: fixed SeqStorageIndex with merge sorting for itervalues over big indexes
TS/EG: Added length() / __len__() support

In preparation of the verbose-flag and to aid offline debugging.
JPM/TS: added field index option DOCS_ONLY for StampType.

(I.s.o. the default DOCS_AND_FREQS_AND_POSITIONS).