Save the spectra in files.

main_file is the name of the root file to save spectra
tag_file is the name of the root file to save tagged spectra
option has the following format :
- ; means save spactra in the current TDirectory
- ( means open a new file
- ) means close the file
- ch means works with a chain i.e. sequence of names with the same pattern.
- option to Zero spectra is given using {opt1:opt2}.
autotime : call automatically this command again after autotime seconds. Off if set to 0.

Here are some examples.

if you have open your watcher is a root directory and would like just to save there the current histograms : "" "0" ";" 0
to save in the current root dir, open a new one and move all hitograms there : "my_new.root" "0" ";(" 0
to dump histograms in a root file (open, save and close the file) : "my_dump" "0" "(;)" 0
to dump histograms in a chain of root files (open, save and close the file) : "my_dump" "0" "ch(;)" 0
it looks for existing my_dumpXXXX.root files in the current dir XXXX = [0, ...[. It takes the first non existing one.
to open a new files that becomes the mother file of all watchers, and save histo there : "my_dump" "0" "(;" 0
to set spectra of the pool to zero : "my_dump" "0" "(; {pool}" 0
to set all spectra to zero and change the binning : "my_dump" "0" "(; {pool:100 0 100}" 0

Definition at line 1473 of file Watchers.cpp.