Adding groups of nuisances
Squashed commit of the following:

commit 9681ecc239a799cef15192887ef694e3726c88c7
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:27:34 2014 +0200

    Adding tutorial cards for nuisance groups

commit 412767980ad658d830f676488228f68286dcba7c
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:24:34 2014 +0200

    No Need to change the comment lines and add back print of discrete parameters

commit 71a5fcafd797f77ccc5df58ba89a61c2b9919e43
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:20:53 2014 +0200

    Remove Printout of RooArgSet

commit e171ca2b727a481b6baf623240be47751ff16b8a
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:08:22 2014 +0200

    Removing .txt files

commit c500a8e650396dd3ea7fc1d8fe099b8385ca5ba1
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:06:58 2014 +0200

    Adding back include-nuisances

commit 83161f190e80c5bc056b8a58ae19969a5f06355c
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 17:01:10 2014 +0200

    More conflict merging

commit 9d8f4dfba241c2f34b29578f9b8fdf159ee6df07
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 16:57:36 2014 +0200

    Fix Conflicts

commit 38f2abf7cd6b717f96855b5ff40e94a35cb8a4a4
Merge: 1ee4231 9f540c6
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 16:50:30 2014 +0200

    Merging Nuisance grouping tools

    Merge commit '9f540c6c7a6364ffb2ca6bcc331e80d8b0497181' into nckw_testing

    Conflicts:
    	interface/Combine.h
    	python/ModelTools.py
    	scripts/combineCards.py
    	src/MultiDimFit.cc

commit 9f540c6c7a6364ffb2ca6bcc331e80d8b0497181
Author: nick <n.c.k.wardle@googlemail.com>
Date:   Mon May 5 16:31:43 2014 +0200

    Get Argsets from workspace to freeze

commit 8117211a1b65b0a31eda4b52accdc6c17242ef66
Author: adavidzh <andre.david@cern.ch>
Date:   Mon May 5 15:50:23 2014 +0200

    Test data cards for groups of nuisances

commit 44f17cc9f02a440ce92c1daf8d5faf198b822f24
Author: adavidzh <andre.david@cern.ch>
Date:   Mon May 5 15:21:24 2014 +0200

    hook notes

commit f3dd1cdf5cccd4a221c3d26bcaccad327e54a008
Author: adavidzh <andre.david@cern.ch>
Date:   Thu Nov 21 16:56:31 2013 +0100

    Added [+=] to group definitions to make sure things are properly specified.
    POI variables now have a group_POI attribute.
    Pedantic treatment of unclear group definitions.
    Python part of what is needed for #32.

commit 6933f75f2d87f5cb15cda70c88900718bdbcc8e7
Author: adavidzh <andre.david@cern.ch>
Date:   Tue Nov 12 01:06:05 2013 +0100

    Command-line option parsing in place.
    Also some orphaned code to how to deal nuisances in a loop over nuisances.

commit 9d578c4d459cd641ca3843fa5768051a932e52b0
Merge: 994a575 b8ee0e9
Author: adavidzh <andre.david@cern.ch>
Date:   Sun Nov 10 19:57:34 2013 +0100

    Merge remote-tracking branch 'origin/groups_of_nuisances' into groups_of_nuisances

commit 994a575192e1e66e90effae378061f549556e6a1
Author: adavidzh <andre.david@cern.ch>
Date:   Wed Nov 6 13:54:40 2013 +0100

    small fixes

commit 5c38a6cbcc3c9c7951b1065e7326af0e1dfb755f
Author: adavidzh <andre.david@cern.ch>
Date:   Thu Oct 31 01:02:09 2013 +0100

    Multiple group definitions are now merged as the union.

commit d7bd3c54f99fef2f20b9848c04e0c562ccb33eec
Author: adavidzh <andre.david@cern.ch>
Date:   Wed Oct 30 23:40:16 2013 +0100

    Changes to implement groups of nuisances #32
    Part 1 - python code

commit b8ee0e9c63dc619053b3a95eae33ade3dada8fa8
Author: adavidzh <andre.david@cern.ch>
Date:   Wed Nov 6 13:54:40 2013 +0100

    small fixes

commit 4ab7c9451255bf9e0b1d3fb9fa74bdacb8d83e86
Author: adavidzh <andre.david@cern.ch>
Date:   Thu Oct 31 01:02:09 2013 +0100

    Multiple group definitions are now merged as the union.

commit c01c894d30d4fa47b218fc058a196562b3020a6a
Author: adavidzh <andre.david@cern.ch>
Date:   Wed Oct 30 23:40:16 2013 +0100

    Changes to implement groups of nuisances #32
    Part 1 - python code
Merge pull request #126 from nucleosynthesis/nckw_add_groups_of_nuisances

Add groups of nuisances
Fix scaling of vector bosons in VEVandEpsilon.py

Now matches the definition of Ellis et at in 1303.3879.
This is also consistent with ATLAS-CONF-2014-010.
Fix scaling of vector bosons in VEVandEpsilon.py

Now matches the definition of Ellis et at in 1303.3879.
This is also consistent with ATLAS-CONF-2014-010.
Fix scaling of vector bosons in VEVandEpsilon.py

Now matches the definition of Ellis et at in 1303.3879.
This is also consistent with ATLAS-CONF-2014-010.
(undoing previous mistake)
Fix scaling of vector bosons in VEVandEpsilon.py

Now matches the definition of Ellis et at in 1303.3879.
This is also consistent with ATLAS-CONF-2014-010.
(undoing previous mistake)
Add option to skip B-only fit in MLF.
Merge pull request #128 from adavidzh/development

Add option to skip B-only fit in MLF.
Fix group behaviour in cards without groups
Add HZZ4l spin-0 property pdfs
Nuisance modification syntax
Add one final fit to fix Methods which need RooFitResult when using discrete parameters
Add back loop over discrete parameters
Closes #137
short script to fill histogram with the number of simulated background events for each toy thrown
Merge pull request #139 from jbrinson/master

Thanks!
extern
change the order of loading snapshot and setPhysicsParameters
add "skipBOnlyFit" for MaxLikelihoodFit to just make a s+b fit only.
Giovanni's piece of code for edit nuisances