Add theory files and little update to the limits plot

@farooque ,

I added some text files with the HBSM cross sections which we previously stored in a random place on lxplus. Plus I uploaded a modified version of DumpLimits.py

Given that there are some style differences compared to VLQ and that it's getting a bit long I preferred to upload one more copy. Everything is under macros_nicola so this change doesn't affect anybody