Improved BOZ flat field

• adds low and high threshold on product and ratio of ROIs to calculate flat field correction
• adds default flat field guess for the fit as parameters
• implement hexagonal lattice for DSSC pixels
• breaks left/right symmetry for flat field fitting since zone plate can be slightly rotated
• implements a refine fit with regularization for flat field calculation
• implements dask auto rechunking

Closes #53 (closed) #55 (closed)

doc/changelog.rst

@@ -11,6 +11,8 @@ unreleased
     - fix :issue:`46` with a change in dask groupby mean behavior :mr:`174`
     - fix :issue:`47` SLURM script not using the correct kernel :mr:`176`
     - fix :issue:`51` make sure that BAM units are in ps :mr:`183`
+    - fix :issue:`50` and :issue:`54` relating to package dependencies
+		- fix :issue:`57` adds target mono energy mnemonic
 
 - **Improvements**