Changed behaviour of @dynDates/display.
Added @dynDates/union function.
Added a routine to convert variable names with underscores into somthing readable by a tex processor.
Deduce tex names from the names of the variables in dynSeries objects.
Make load and save routines for dynSeries objects support tex variable names.
Changed behaviour of @dynSeries/uminus and fixed bug.

 + Prefix variable names with the minus symbol.
 + Set tex member.
Changed copyright year.
Changed behaviour of @dynSeries/ydiff (name  of the variables).

 + Prefix variable names with YDIFF_
 + Prefix tex variable names with \Delta_i with i=nothing, 4, 12 or 52 depending on the frequency.
Added unitary test for @dynSeries/ydiff.
Changed behaviour of @dynSeries/qdiff (name  of the variables).

+ Prefix variable names with QDIFF_
+ Prefix tex variable names with \Delta_i with i=nothing or 3 depending on the frequency.
Changed behaviour of @dynSeries/ygrowth (name  of the variables).

 + Prefix variable names with YGROWTH_
 + Prefix tex variable names with \delta_i with i=nothing, 4, 12  or 52 depending on the frequency.
Changed behaviour of @dynSeries/qgrowth (name  of the variables).

+ Prefix variable names with QGROWTH_
+ Prefix tex variable names with \delta_i with i=nothing or 3 depending on the frequency.
Fixed bug (added missing tex member to extracted variables).
Removed useless test.
Removed useless condition in @dynSeries/subsasgn.
Changed unitary test.
Changed default names for the variables.

If the names of the variables are not provided when instantiating a dynSeries object
then the default name is of the form Variable_i (i=1,...,N, where N is the number of
variables in the dataset).
Added missing tex member in @dynSeries/merge method.
Removed useless deblank command.
Added unitary test in @dynSeries/merge.