Replaced std::vector<SharedHandle<PieceStats> _sortedPieceStats
with std::vector<size_t> _sortedPieceStatIndexes to reduce the
cost of std::rotate().
* src/RarestPieceSelector.cc
* src/RarestPieceSelector.h
* test/RarestPieceSelectorTest.cc
Put piece selection strategy algorithm to RarestPieceSelector
class,
Added a switch to choose whether randomized selection so that
unit
tests emit same results in, possibly, win32.
* src/DefaultPieceStorage.cc
* src/DefaultPieceStorage.h
* src/RarestPieceSelector.cc
* src/RarestPieceSelector.h
* test/DefaultPieceStorageTest.cc
* test/RarestPieceSelectorTest.cc