New version of Pythia8, 226, in view of Sim10

Update generators_versions.txt to use new version of Pythia8, 226 - do not dot it for cmt since it is no longer supported with versions of Gauss post-Sim09

added ToMaster label

• [2017-07-27 00:03] Validation started with lhcb-gauss-dev#1342
• [2017-07-27 00:15] Validation started with lhcb-gaudi-head-noavx#82
• [2017-07-27 00:15] Validation started with lhcb-head#1548
• [2017-07-27 00:16] Validation started with lhcb-lcg-dev3#232
• [2017-07-27 00:16] Validation started with lhcb-lcg-dev4#232
• [2017-07-27 00:16] Validation started with lhcb-clang-test#655
• [2017-07-27 00:17] Validation started with lhcb-gaudi-head#1545
• [2017-07-27 00:26] Validation started with lhcb-gaudi-head-noavx2#63
• [2017-07-27 10:10] Validation started with lhcb-clang-test#656

merged

mentioned in commit 0ce99f8c

added ~2736 and removed ToMaster labels

changed milestone to %Gauss v52r0

removed 1 deleted label