Fixed bug. Missing definition of time member in @dynSeries/merge method.
Added test in @dynSeries/check method.
Cosmetic change. Removed commented line of code.
Added unitary test in @dynSeries/extract method.
Added the possibility to factorize the extraction of variables from a dynSeries object.

In addition to the already implemented selection mechanism using matlab's regular expressions,
we allow the following syntax:

a = ts{'GDP_@US,JP,FR@'};

to extract variables GDP_US, GDP_JP and GDP_FR from dynSeries object ts. If one of these variables
does not exist, an error message is issued.
Fixed bug.
Fixed bug.
Fixed numbering of the unitary tests in @dynSeries/subsasgn method.
Fixed bug.
Added routine.
Closes #333
Added unitary test in @dynSeries/subsasgn
Closes #346