Allow the user to choose if re-using a SVI field or recalculating the SVI. GUI logic done. Missing calculation logic
Attempt to fix logic to allow the user to choose between re-calculating SVI or using an existing SVI attribute, while calculating the IRI
Remove combobox 'zonal attribute name' from attribute selection dialog, because it is not used anymore
Add unweighted sum combination type
Add to combination types also the simple (unweighted) multiplication
Merge pull request #44 from gem/draw-iri-use-existing-svi

When calculating the IRI, allow the user to choose if re-calculating the SVI or using one of the available fields
Define default combination type in globals and import that everywhere it's used, instead of duplicating
Merge branch 'draw-iri' into draw-iri-improve-combining-operators

Resolved conflicts in:
	svir/calculate_iri_dialog.py
	svir/ui/ui_calculate_iri.py
	svir/ui/ui_calculate_iri.ui
Use default combination type also where it was missing
Merge pull request #46 from gem/draw-iri-improve-combining-operators

Add some combining operators
Set default new attribute name when selecting transformation and variant
Better handling of new attribute name in transformations
Merge pull request #47 from gem/simulate-add-attrs

Dynamically manage the default name of transformed attributes
Merge branch 'draw-iri' into draw-iri-fix-log10-zeros-management
Enable transform_attribute action only if a vector layer is selected. Otherwise keep it disabled.