Core: strategy features

Some new features are required for the strategy tool:

• Optimise starting angle (omega) for the scan
• Rotate the sample by some value (kappa), then optimise the strategy for 2 combined runs.
• Plot as in HKL2000 for guessing the best starting point
• Predict overlaps, these change with crystal shape and wavelength. Wavelength should be an adjustable parameter.
• Add resolution shell completenesses to strategy.
• "Artificial" output as .x or .sca file (i.e. positions and miller indices without intensities)