Make analysis yml accessible everywhere (-> split samples); also add modulo operator

• Provide the sample config (from the analysis config) to the prepareTree, definePlots analysis methods
• Forward the file to the worker jobs
• Note: worker jobs do not replace all the files (no database access and such), I don't see why that would be needed (it would also require forwarding the environment .ini config)
• Also add the modulo operator for int proxys

This makes it possible to split files easily (fixes #39 (closed)), e.g.:

samples:
  ttbb:
    files: ['ttbar.root']
    subprocess: ttbb
  ttjj:
    files: ['ttbar.root']
    subprocess: ttjj

and in prepareTree():

if "subprocess" in sampleCfg:
    subProc = sampleCfg["subprocess"]
    if subProc == "ttbb":
        noSel = noSel.refine(subProc, cut=(tree.genTtbarId % 100) >= 51)
    else:
        noSel = noSel.refine(subProc, cut=(tree.genTtbarId % 100) < 51)