Added --deep option for genreflex

The --deep option is now available for genreflex.
It is properly percolated into the call to rootcling although
not needed via rootcling since not needed, at lest at the moment.
Added to genreflex --deep and -l option. Minor bugfixes.

--deep is an existing option of genreflex.
On the other hand -l (--library) was added to genreflex to percolate
the -s option of rootcling, which is the name of the lib where the
dictionary of the class will exist.
Unfortunately -s was dedicated to the selection file and a new
switch had to be create.

Some of the options were not properly picked up since they were
wrongly specified in the parser (--myOpt instead of myOpt).

A wrongly allocated array of char* was replaced by an std::vector,
then passed over to RootCling as char** exploiting the
"&v[0] property".