Adjust fftw3-sys Cargo.toml for crates.io.
Adjust RawPlan::new to avoid panicking.
Use RawPlan in the builder.
Add inplace c2c support.
More assertions.
Switch to using the guru interface internally.
Switch to the guru64 functions.

These will always work, even for huge transforms.
Add some proper tests for the builder.
Make iodim fields public.
Add test for iodim FFI.
Update for numeric reform.
Switch to by-value builder, move dimension/multiples handling to Planner.