Support edn file extension.

.edn seems like a more appropriate extension for a clojure data file
that is not intended to be executed.
More flexible multimethod extension

Its possible to add methods to an existing multimethod, but if you want
to do the exact same thing as an existing mutlimethod using a different
tag then you can derive iff the dispatch value is a namespace qualified
keyword.
Read on stream rather than string

PushbackReader expects an implementation of reader-types Reader protocol.  This protocol does not support as many input sources as slurp, but all sources supported by slurp are supported by io/input-stream which does have a Reader protocol implementation.
Add support for other io types

Should be possible to specify a string or file resource without
converting it to a URL
Update documentation

Bumped version to 1.1.0 due to changes in multimethod dispatch tag.
Updated documentation to specify how one can add support for additional
file types and/or extensions.
Documentation fixes.
Fix documentation
Use snapshot version until merged and released
Update version in documentation
Merge pull request #16 from sonian/ednsupport

EDN extension support