multiple fullstack nits/cleanups before release

[jkelleyrtp]

This PR incorporates a number of fixes and nits related to fullstack.

• serverfn url with /:syntax
• fix template error in encode/decode cases (1/2 done so far)
• query params should allow :params or {params} as catchall
• query params should allow a=b to allow renaming parameters
• custom repsonse headers
• fix hotpatch with serve setups 🤦
• implement automatic chunking for Streaming<T, E> types
• fix Lazy initializer
• get custom State working

later...

• custom request headers
• filestream native from bytes
• automatic multi-encoding on server