Bump piggieback version to 0.1.2
Since version 0.1.0, Piggieback no longer requires an explicit
setup prior to
cemerick.piggieback/cljs-repl (c.f. https://github.com/cemerick/piggieback/blob/c6d1406eb2b21cfa74e53521a293d91641b375c0/CHANGES.md#010
)

This was causing problems while starting a new session with run-node-nrepl
Bump version to 0.1.11
Changed working version to 0.1.11-SNAPSHOT, for development. Whenever
this gets merged to the upstream repo and released, it should be changed
to the release version
Also changed the README to point to the proper current version
Finally figured out (and fixed) what was wrong when using the latest
Piggieback (0.1.2) and ClojureScript.
There's now a compiler environment that should be set before evaluating
forms. I've now added it to the setup function and to the repl-env. It
uses cljs.repl/default-compiler-env
Merge pull request #13 from dzacarias/master

Update to Piggieback 0.1.2 and add support for cljs.repl compiler environments