fix(filters): Align behavior with shopify/liquid

- Coerce values to strings
- Be looser about error handling
- Support `slice` on `Array`
- Add defaults to various filters
- Support windows line endings
- Note unsupported parameters

The string coercing makes this more allocation heavy.  This can be
mitigated by having `Value` use `Cow`.  In contrast a couple of
allocations were removed when doing string concatenation.