Skip 'nil' environment values when iterating.
Refactor tiered hash lookup to common method; allow overwrite of http headers; allow storing 'nil' in the fronting hash.
Delete #load_headers which is no longer used.
Fix call to getServerInfo.
Add parens to avoid warning in verbose mode.
Be more flexible in sketchy means of finding jruby_home (FIXME: surely there is a better way?).
Add logback config to quiet down Jetty during integration tests.
Set sub-ruby BUNDLE_GEMFILE sooner.  Invoke 'bundle install' directly rather than via 'system'.
Remove extraneous 'puts'.
Use env var to set Rails' relative url root as it seems more robust across versions.
Add integration test for Rails 3.1.
Make Rubylet::Environment extend Hash to conform to Rack SPEC.
Set binmode and ASCII_8BIT encoding on the input stream to comply with Rack::Lint.