Use Rails.initialize! where we just want to run the initializers and aren't concerned about the config

Restores accidentally-reverted commit.

Signed-off-by: NYehuda Katz <wycats@gmail.com>

Fix a few more 1.9 bugs. Rack 1.0.1 is required for 1.9 compliance but not release, so bundling 1.0.1 from git

Have config/application.rb contain the application definition and require that file instead of config/boot.rb or config/environment.rb in script/*.

This reverts commit 8cbf8254.