Add ubyte function

Add function ubyte that takes an integer value and returns a signed byte
whose byte value is equivalent to the first 8 bits of the provided int,
e.g. (ubyte 255) -> -128.
Adds support for adding an image

This commit adds support for sending images, or any other kind of binary
data.  Bit of  big change made...resource functions now return a byte
array.  There was a problem with sending binary read from a file as a
string.  It would be cleaner to add a function that coerces data into a
byte array instead of expecting it.

There is also a change made to the response returned by gen-response.
It now returns a map structure in a similar manner to extract-req.

Add predicate function accept-gzip? that tests if the user agent will
accept gzip encoding as a response.

Remove :post and :head method functions until new changes are ironed
out.

Replace write-to-socket with different function write-response-to-stream
that write the mapped response data to a stream, using new function
write-string-to-stream.
Remove some header functions

Removed most of the header functions as this output is now generated in
write-response-to-socket.  Remove \r\n returned when creating the
response line.  Fixed Date header to (correctly) provide the Date token.
Add extension type mapping

Adds a map reference for storing file extension to content type
mappings.  Includes a function for creating them, as well.
Add unit tests

about time
add to ignore

now ignore .lein-failures file