Make ActiveSupport::Benchmarkable a default module for ActionController::Base, so the #benchmark method is once again available in the controller context like it used to be *DHH*

With this commit, ActiveRecord will also look for migrations
in db/migrate subdirectories.

49ebe51 fixed copying migrations, but existing migrations would still
trigger warnings. The proper way to compare migrations is to ignore
origin lines - if migration is identical it means that we can
silently skip it, regardless where it comes from.

There was a bug in ActiveRecord::Migration.copy method, which
prevented adding special comment about the origin of migration.

Because of that, the check if migration is identical or if it's
not and should be skipped was always saying that migration is
skipped, which was causing additional useless warnings about
skipped migrations.

Removing this feature causes boost in performance when using Ruby 1.9.

Ruby 1.9 started to do implicit conversions using `to_ary` and `to_str`
in some STDLIB methods (like Array#join). To do such implicit conversions,
Ruby 1.9 always dispatches the method and rescues the NoMethodError exception
in case one is raised.

Therefore, since the whiners feature defined NilClass#method_missing, such
implicit conversions for nil became much, much slower. In fact, just defining
NilClass#method_missing (even without the whiners feature) already causes a
massive slow down. Here is a snippet that shows such slow down:

    require "benchmark"
    Benchmark.realtime { 1_000.times { [nil,nil,nil].join } }

    class NilClass
      def method_missing(*args)
        raise NoMethodError
      end
    end

    Benchmark.realtime { 1_000.times { [nil,nil,nil].join } }

Add dependency status (a la build status) to the README

Fix a failure in railties on ruby 1.8.x

In Ruby 1.8.x, config.encoding sets $KCODE.
Therefore, the possible values are UTF8, SJIS, or EUC.
And, if we set SJIS, we'll has the error. Because some rails sources are written in utf-8 encoding.

Fix warning for params_wrapper_test.rb