Updated the NumberOfProcessedEvents for each sample.
Also checked the cross sections with those available in the 8TeV Cross Sections twiki:
(WJetsToLNu is different in the twiki but we do not use it so left unchanged.
T and Tbar t-, s- and tW-channel cross sections are *very* slightly different (<0.1) so left unchanged.)
Corrected a couple of typos.
Merge pull request #26 from jjacob/master

Updated python/DataSetInfo_8TeV.py