Add several handy commands and scaler analysis feature

[shkawase]

Added commands

• fls: show TFile list
• fcd: change gDirectory to some TFile
• fipo: Fit by POlynomial
• rg(x|y|z): invoke TAxis::SetRangeUser()
• unzoom: invoke TAxis::UnZoom()

Scaler analysis

Scaler data will be stored in UserInfo in the current artemis tree as art::TScalerData. The data will be added in the THashList named "scaler". You can retrieve them from CINT or your processors by putting something like

tree->GetUserInfo()->FindObject("scaler")->Print();