some comments about maybe things todo with iterator code and use std::move() stuff / r-value references with Optional<T>
try a few more uses of std::move() - untested so far
fixed typo
minor cleanups and fixes (missing CTOR) to BLOB code
minor fix to Date code (AddDays now consant method - not chaging date object); but lots of other docs changes to Date code, and using Define_Start_End_Count macro
fixed date regression test to accomodate recent change in meaning of AddDays()