Bryn updates

Hi Ted,

This "fixes" `oneHisto` and `ratio` for dealing with histograms that are in the top-level directory of the ROOT file.

It also adds two new functions for dealing with Bryn's proposed changes to the format of the cross-section and efficiency scans he provides us.

I would hold off on merging this as there's a few things I wanted to discuss about it[1], but wanted to bring it your attention nonetheless.

[1] I get crashes still when running in the mode before these changes were made (but just for tanBeta X). The crash comes from the cleanup that the pdf creation does.

```python-traceback
RooFit v3.52 -- Developed by Wouter Verkerke and David Kirkby 
                Copyright (C) 2000-2012 NIKHEF, University of California & Stanford University
                All rights reserved, please read http://roofit.sourceforge.net/license.txt

TUnixSystem::SetDisplay:0: RuntimeWarning: DISPLAY not set, setting it to pb-d-128-141-142-24.cern.ch:0.0
   **** Error: Cannot find a %%EOF marker anywhere in the file.
   **** Warning:  An error occurred while reading an XREF table.
   **** The file has been damaged.  This may have been caused
   **** by a problem while converting or transfering the file.
   **** Ghostscript will attempt to recover the data.
Error: /undefined in --run--
Operand stack:
   (/tmp/gs_Cs0W8T)   --nostringval--   3   --dict:5/5(ro)(G)--   (e)
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1846   1   3   %oparray_pop   1845   1   3   %oparray_pop   1829   1   3   %oparray_pop   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   --nostringval--   %loop_continue   --nostringval--
Dictionary stack:
   --dict:1150/1684(ro)(G)--   --dict:1/20(G)--   --dict:75/200(L)--   --dict:75/200(L)--   --dict:106/127(ro)(G)--   --dict:285/300(ro)(G)--   --dict:20/25(L)--
Current allocation mode is local
GPL Ghostscript 8.70: Unrecoverable error, exit code 1
==> Warning: BoundingBox not found!
EPSTOPDF 2.9.3draft, 2003/04/20 - Copyright 1998-2002 by Sebastian Rahtz et al.
!!! Error: 'output/CLs_asymptotic_TS3_tanBeta10_nlo_RQcdFallingExpExt_fZinvTwo_55_0b-1hx2p_55_1b-1hx2p_55_2b-1hx2p_55_gt2b-1h_validation.pdf' does not exist!
Traceback (most recent call last):
  File "./stats.py", line 135, in <module>
    plottingGrid.makePlots()
  File "/home/hep/sr505/RA1/ra1stats/plottingGrid.py", line 473, in makePlots
    multiPlots(tag = "validation", first = ["excluded", "upperLimit", "CLs", "CLb", "xs"], last = ["lowerLimit"])
  File "/home/hep/sr505/RA1/ra1stats/plottingGrid.py", line 370, in multiPlots
    logZ = ["xs", "nEventsHad"], switches = s, suppressed = suppressed)
  File "/home/hep/sr505/RA1/ra1stats/plottingGrid.py", line 290, in printOneHisto
    utils.epsToPdf(eps)
  File "/home/hep/sr505/RA1/ra1stats/utils.py", line 117, in epsToPdf
    if removeEps : os.remove(epsFileName)
OSError: [Errno 2] No such file or directory: 'output/CLs_asymptotic_TS3_tanBeta10_nlo_RQcdFallingExpExt_fZinvTwo_55_0b-1hx2p_55_1b-1hx2p_55_2b-1hx2p_55_gt2b-1h_validation.pdf'
```