Remove unused code
Make Dummy adapter the only REPL implementation
Remove ActiveRecord and mutex from REPL class
Let the middleware handle repl_session routes
Move REPLSession model to lib/
Remove unneccessary engine stuff
Remove irrelevant tests
Merge pull request #16 from ryandao/cleanup

Cleanup
Retrieve source code for the whole stack trace
Rename sources_extract to extract_sources
Use map instead of each in extract_sources()
Prevent the href default behavior when navigating stack trace
Add ExceptionWrapper test
Re-include exception_wrapper