DateRanges are with Next/Prev

The new LastMonthsDateRanges enum allow the use of a new overloaded
function called:
public bool SetDateRange(DateTime end, LastMonthsDateRanges range)

This function is for showing multible last months.
This is more natural that the forward-original one so that there is no
need to change manully the dates to achive the desired outcome.

In addition, There is new SetFilterDateRangeForward function in
TransactionGetterStringFactory that allows to move forwards and
backwards the dates with its own range, so again, the outside world
should not know how to handle date ranges.