ToString tests

Money ToString

Best Inverse test

Added inverse rates and refactor for double rates

Test Inverse rate

Refactoring amount to be double

Undo last test

Test sum of same currency money

Times() to MoneyExpression interface. Fixed Sum Plus to return not null

Added SumPlus test

Chanegd test

Money expression interface added Plus

Sum reduce changed to make test pass

Fixed test to compile but still red

mixed currency add test