Remove WasExternal::BlockFit and associated code
Remove WasExternal::Energy_study
Remove WasExternal::NoCatag and ForceCatag

These two variables were related but never used.
Remove WasExternal::FreeGlobals
Remove WasExternal::DoGlobal

There were two places in Yiqun where this flag was used, executing
code when DoGlobal was true:
1) Yiqun::Fit2PhotonClust() performs global fit to recalculate chi2
2) Yiqun::FitEvent() performs global fit when nRealClusts > 1
DoGlobal was always set as true in the code up to this point.
If DoGlobal were set to false neither of the above things would
happen; in particuler there would be no fitting when nRealClusts > 2.
As the default (true) seems like the sensible option, we remove the
flag entirely.
Remove WasExternal::SubClu2
Remove WasExternal::dev and dchi2

Looking at Steve's original package, I found these matrices were
only used in making QA plots and aren't needed here.
Remove shower-related variables from WasExternal

showerShapeFunc, showerWidthX and showerWidthY were all given default
values that caused them to have no effect in the code. As these defaults
values were never changed (even in Steve's original full version of the
code) there seems no reason to retain them.
Remove WasExternal::choiceChi2

This variable was set to 2 and never changed. I was unable to find an
example in Steve's original package where it was changed either. I
therefore deleted both it and any portions of code that only executed
for values other than 2, as these were never reached.
Remove WasExternal::UseThis_ab

This flag was effectively always true. Therefore remove it and related
code. Set the defaults for WasExternal::a and ::b parameters to the
appropriate values so they no longer need to be set in StFmsHitMaker.
The a and b parameters should be moved from WasExternal to FitTower at
some point, but I will do that later.
Remove WasExternal::UseEDepCorrection

This flag was always true, so it is removed, along with any conditional
statements related to it and the FitTower method to set it.
Remove WasExternal::useLimitForPara

Though there were conditional statements that did different things for
different values of this parameter, it was never changed from its
default value of 1. Looking at Steve's original longer code I could not
find anywhere where it was modified either. Therefore it is removed,
along with conditional parts of the code that were never executed.
Remove WasExternal::Force2Mass

Steve occasionally in his original code used this, presumably to force
the photon-pair mass to the pi0 mass. However, he generally didn't.
That is the behaviour currently in the code and, I imagine, what we
want, so I removed the flag entirely. I eliminated associated code, as
it was never called.
Remove error-related factors from WasExternal

Remove errFactor, errQ, Power1, Power2 and UseThis_Err members. This
change does introduce a slight difference in behaviour to the prior
state of the code. This is because previously the UseThis_Err flag
was always false. This caused a particular error calculation to be used
in FitTower::Fcn1(). However, looking at Steve's code his macros
typically call FitTower::Setwe_ErrFactors() to set the first 4 values.
This causes UseThis_Err to actually always be *true*. The result is a
slightly different error calculation being used. Because we still use
the default values for errFactor etc the difference ends up being small
but it is there, so I note it here. However I think this change makes
the behaviour more closely resemble that of Steve's original package.
I also deleted some other related code, such as parts that are no longer
executed, including the previously used error calculation.
Replace use of WasRandom::myRand

Yiqun used this random number generator in one place. It was a TRandom
object, which the ROOT developers warn is a bad random number
generator. It also had the same seed for every run. Therefore we remove
it, and use the global ROOT random generator via gRandom, which is a
superior TRandom3 generator.
Move tower fit parameters from WasExternal

The function parameters are now set directly in FitTower, where they
are used. There is a very slight change in output, because the
parameters stored in WasExternal were floats, which caused a small loss
in precision. Now doubles are used.
Rework FitTower shower shape fit function

Remove function declaration from WasExternal, entirely in FitTower now.
Eliminate the separate instance in each FitTower, copied from the static
instance. Each FitTower still updates the parameters of the shared
function as before, which may need to be addressed. Instead of being a
static member of FitTower, it is now defined in an unnamed namespace in
the FitTower source file. Still publicly accessible via
FitTower::GetFunctShowShape().
Remove 'step' from WasExternal

This array was set in WasExternal then copied to FitTower without
modification. It is therefore now just stored in FitTower. While
used by Yiqun also, it can always be accessed via the FitTower that
Yiqun stores, so it doesn't need to be external. Yiqun did have its own
step array as well, but it didn't seem to be used for anything, so it
was also deleted.
Move widLG from WasExternal

This "width of lead-glass" variable was only used within FitTower, so
it made more sense to keep it there. It is now a static member of that
class.
Move tow2Fit from WasExternal

This array of towers is filled in Yiqun, then only used in FitTower, so
it makes more sense to store it there than in WasExternal. It needs to
be static as it is utilised in a static function, to interface with
TMinuit.