- Allow users to specify full model compilation when using
`input_signature`, which allows for complex collection-based inputs
- Enable "psuedo-partitioning" phase for input collections as well as
output collections
- Update `OutputIsCollection` to include dictionary outputs, and add
function `InputIsCollection` to detect collection-based inputs during
graph compilation
- Remove automatic fallback for collection pack/unpack operations when
using `input_signature` argument
- Add collections tests to ensure full compilation is respected for
input and output collections

- Add documentation to `README` for usage of input signature
- Add documentation to "Getting Started" page for usage of input
signature