Add func assoc-in-many

Returns the result of associating with reduce many different key paths /
values into a map.
take a map-value for :res-ln instead of a string

Changes the assumed value when writing a response line to the output
stream in write-response-to-stream.  Now expects a map with the child
values of response line (instead of a string)
Change response-line function to return map
Pass resource functions response arg

Adds a response argument to the macro-generated headers of resource
functions, so that a resource function has finer control over the sent
content.
Permit resource functions to return a response map

Adds support for allowing resource function return either a byte array
or a response map.
Update tests