New functions to request calculations.

src/lib/calculations.ts

src/lib/components/test_cases/TestCaseEdit.svelte

src/lib/components/variables/VariableInput.svelte

...omponents/variables/VariableReferredScaleParameter.svelte

...omponents/variables/VariableReferredValueParameter.svelte

src/lib/components/variables/VariableView.svelte

src/routes/__layout.svelte

src/routes/index.svelte