Fixed bug in @dynSeries/subsasgn that pops up when length(S) is equal to two and S(1).type is a dot.

Allows Syntax like:

ts.A1(rg) = B

where ts is a dynSeries object, A1 is a variable in the database, rg is a dynDates object and B an array of doubles.
Added broadcasting when assigning new data to a dynSeries object.

*Examples*

 * ts.A(qq(1950,1):qq(1950,4)) = 1 will put ones for variable A in periods 1950Q1 to 1950Q4

 * ts{'A','B'}(qq(1950,1):qq(1950,4)) = 1 will put ones for variables A and B in periods 1950Q1 to 1950Q4

 * ts{'A','B'}(qq(1950,1):qq(1950,4)) = ones(4,1) will put ones(4,1) for variables A and B and sub-periods 1950Q1-1950Q4

 * ts{'A','B'}(qq(1950,1):qq(1950,4)) = ones(1,2) will put ones(1,2) for variables A and B and each period between 1950Q1 and 1950Q4
Fixed bug related to broadcasting in dynSeries objects.
Cosmetic change.
Added unitary tests.
Added overloaded vertcat method in dynSeries class.

*Exemple*

Suppose ts1, ts2, and ts3 are three dynSeries objects with the same variables. Then

ts4 = [ts1; ts2; ts3]

is a dynSeries object with the observations contained in ts1, ts2 and ts3 (in that order).
Changed unitary tests (check also the number of observations).