Add WIP positional compilation as a separate namespace, for now
more informative error message
Incorporated positional compile to replace eager-compile.

This is largely an export so Jason can take a look; I still plan to clean
things up.
Clean up structure of positional.

I attempted to address Jason's "code smell" comment about separate functions
for efficient call forms and efficient functions. I'm not sure I succeeded.
Cleaned up a bunch of things with Jason's help.
Moved positional library into graph subdirectory.
Neuter positional-test for now
Abstract out extraction of a positional fn from graph compilation
Abstract out a single place for creating positional fnks
Minor reorg
Partial docs pass, move comp-partial into graph
Normalize indentation and remove trailing whitespace
Add positional-eager-compile composition so users don't have to look into fnk-impl
Normalize eager-compile docstring
Add a test for positional-fnks via positional-fn
Fix graph tests and add tests for new positional compilations
Update changelog to mention change to lazy-compile
All tests pass
Add supported clojure versions and profiles to test all (thanks ClojureWerkz)
Fix examples in readme, and mention perf improvements