TS/JPM: moving index into sequential storage, started by extracting MultiSequentialStorage from sequentialstorage.py
TS/JPM: work in progress: SequentialStorage that works with 'identifier', fixing bug in _SequentialStorageByNum._lastKey determinination at startup.
TS/JPM: SequentialStorage is now self-contained (incl. own index that maps identifiers to keys/stamps and version number); clearly separated MultiSequentialStorage and StorageComponentAdapter
TS/JPM: __getitem__ KeyError encapsulation improvement
TS/JPM: rename AddDeleteMultiSequential -> AddDeleteToMultiSequential to make direction more explicit.
TS/JPM: started offline garbage collecting; sorted merge policy and collector
JPM: using NumericRangeQuery to query for number keys in batches during GC
JPM: 'optimized' GC by introducing '_SequntialStorageByNum.copyTo' that saves on decompress+compress step per record.
TS/JPM: optimized SequentialStorage._Index.itervalues() by making fast collectedValues() method on SeqStoreSortingCollector
TS/JPM: further optimization by making copyTo run over original file instead of using getMultiple
TS/JPM: added development sys path extensions
JPM: removing temp file if it already existed at start of GC
TS: renamed constant.
TS: removed keepCompressed where unused, renamed to _keepCompressed and added warning signs.
TS/JPM: more test coverage, skipDataCheck and verbose flags added.

TODO: implement verbose & skipDataCheck.
JPM/TS: copyTo and _readNext extended for skipDataCheck=False.
TS/JPM: _SequentialStoreByNum.copyTo faster in case first key not at start of file
TS: added build-deps.txt, build on testsetup.sh too.
TS: removed commented code (now definitly obsolete).
TS: moved Weightless to test-deps.