Initial commit of code supplied by David
First attempt to capture metadata in CIF framework.
Further improvement of normalisation and efficiency correction routines
Many changes to ease development and adjust to Echidna
Merge my workflow with official Gumtree workflow
Finished initial writing of efficiency input and correction application

There are still some bugs as seen by strange peaks in an efficiency-
corrected Vanadium data collection.
First draft of efficiency correction calculation and vertical offset
Finished calibration calculations and UI. Preliminary check of reduction

The calibration calculations now calculate vertical offset and efficiency
files.  These can be fed into the reduction routine and work correctly at
least for the Vanadium dataset used initially.
Further improvements for efficiency and included extra initialisation file
Added Split Scans routine and alternative output format
Add PyCIFRW support files for CIF input/output
Added datapoint merging
Initial implementation of overlap routine
Finished initial gain re-refinement and normalisation.

Added test suite which contains normalisation tests for variance, value
and metadata.
Split out calibrations, finished background subtraction and tests
Added tests of vertical shift, fixed small bug
Improved metadata storage and testing coverage. Added a cache for
efficiency files to improve speed.
Converted reduction metadata to use CifFile; fixed regain calculation

All metadata provided by the reduction process is now stored in a CifFile
object within the Dataset. An error in gain variance calculation was fixed
and gain recalculation metadata added.
Split calibrations into separate file and added output format choice
Added and tested the Ford and Rollett gain correction, improved testing framework.