Fix the DDPlanarDigi algorithm to run like the processor

[jmcarcell]

some things I found when comparing the output histograms.

BEGINRELEASENOTES

• Change the default value for the time resolution to -1, which will mean no time smearing by default.
• Use the histogram service to save histograms instead of saving our own files (which meant that if the algorithm runs multiple time there will be multiple files, or a single one if the name is the name for all of them with the content of the last one that was saved).
• Other minor changes like removing an unnecessary header or changing and to &&.

ENDRELEASENOTES

[jmcarcell]

If there aren't any complains, the last time I checked this it seems to be running exactly like the processor, with the only difference that the histograms are saved in alphabetic order in the ROOT file but this is coming from Gaudi.