Adapt the expectation to test's output.
Typo.
Add 'expected' output to the test.
Do not complain about undefined symbols in the lib on MacOS.
Functions can have more than one candidate for differentiation.

For each candidate (top-level decl for differentiation) we need to create a diffplan.
Catch newly implemented issued notices.
Add XFAIL to tests handling functionality that is about to be implmeneted.
Addapted FunctionCalls to match the idea of the custom_derivatives namespace.
Denotion of derivative argument starts from 0 instead of 1.
Add new ray tracer demo, based on smallrt.
Fix some types and frame buffer name error.
Fix file writer. For now program require compiler -O3 option.
Solid structure is now an abstract class with two virtual methods (intersect and normal). A new class for spheres is added (successor of Solid). Normal vectors of the spheres are calculated by performing AD to the implicit. The Scene is now polymorphic array.
Synthesize a FloatingLiteral if the DRE's type is not integral.
Loosen a bit the 'has same type' assert. The new implementation drops the cvr quals when comparing.
Move the assert below. We should rely on the BuildBinOp to do some type conversions first.
Move the assert below. This would allow the BuildBinOp to perform some extra type conversions.
Add proper CHECK-NOT clause, making diagnostics more obvious to FileCheck
Change implicit function with distance function. Rewrite intersection method to use sphere tracin algorithm for distance functions. Add built in implementtions for sqrt derivatives.
Fix built-in derivatives for sqrt.
Add initial support for f(g(x))' -> f'(x) * g(x)'
Cosmetics.