Allow to specify which situation to calculate.

src/lib/calculations.ts

src/lib/components/WaterfallView.svelte

src/lib/components/test_cases/TestCaseEdit.svelte

src/lib/components/test_cases/TestCaseView.svelte

src/lib/components/variables/FormulaView.svelte

src/lib/components/variables/VariableInput.svelte

src/lib/components/variables/VariableReferredInputs.svelte

...ib/components/variables/VariableReferredInputsPane.svelte

...omponents/variables/VariableReferredScaleParameter.svelte

...omponents/variables/VariableReferredValueParameter.svelte

src/lib/components/variables/VariableView.svelte

src/routes/__layout.svelte

src/routes/index.svelte

src/routes/variables/[variable]/index.svelte

src/routes/variables/[variable]/inputs/[date].svelte