Supercharge Rust functions with implicit arguments using CGP v0.7.0

CGP v0.7.0 has been released, bringing a major expansion to the CGP macro toolkit. The centerpiece of this release is a suite of new annotations — #[cgpfn], #[implicit], #[uses], #[extend], #[useprovider], and #[use_type] — that let you write context-generic code in plain function syntax with dramatically less boilerplate than before.