Complete restructure work:
--------------------------

Merge current mast in

Make sure we can start the willmot engine - also dcwillmot differs from dcyou in only two places

Fix and sure have tests (or delete startup files):

	append_diffcalc_to_gda_jython_path.py
	b16fivecircle.py
	b16fourcircle_you_engine.py
	i10fourcircle.py
	sixcircle_api.py
	sixcircle_vrmldummy.py
	sixcircle.py

Check for 3 failing math (at least on OSX):
	- 

Remove _diffcalc module:
	- comment as you go!
	- checkub -> add test to test_you.py
	- fix the 'help ub' and 'help hkl' commands
	- get hkl scannable working without _diffcalc


Tidy:
	- move sim logic off: DiffractometerScannableGroup 
	- move example folder up into diffcalc.gdasupport package
	- rewite documentaion to call actual code for tests
	
Improve:
	- you.py should not skip creating any scannables for fixed constraints (or related ones) 

Compare number of tests again branch point
Decision not to dump vlieg mode
why no integration test for willmott






List needs review. Unordered. RobW.
----------------------------------

- look at all commands together (showref, listub, cons)

- overide help command. Perhaps just print __doc__ if it starts with '!' or '@command'

- error handling in wrapper. check TypeError depth. Give help inside exception string.

- parameter scannables should return current virtual angle __str__ would also show requestd

- remove need for axis_par scannables - set value, consider e.g. mu scan, and moved from epics. mu scan requires mu to be same level as hkl to work efficiently

- implement mu_eq_nu mode

- add eta_half_delta and mu_half_nu modes

- provide fivec etc plugins (i13 first)

- provide arbitrary virtual names (and check arbitray motor names work)

- provide short cut mode access my number (beamline specific) ? Good idea?

- handle eV / keV properly (wavelength internally, flag to energy_unit equal 'keV' (default) or 'eV'

- Fix .__doc__ help on hkl (metaclass syetm fails under Jython with a java base class)