Removing deprecated rake tasks.

The `rake test:recent` and `rake test:uncommitted` tasks were
deprecated and are now being removed.
fix activerecord/examples/performance.rb#L101 syntax error
Merge pull request #11126 from tumayun/fix_activerecord_examples_performance_rb_syntax_error

fix activerecord/examples/performance.rb#L101 syntax error
mention the removal of `--builder` in 4.0 release notes.
Add DelegationError class. Rasied by delegation to a nil object
linking small rails 4 features image to a bigger one [ci skip]

View a bigger version onclick
https://github.com/rails/rails/issues/11100
Merge pull request #10828 from southpolesteve/delegation_error_class

Create DelegationError class
Merge pull request #11128 from edg3r/patch-1

linking small rails 4 features image to a bigger one
Merge pull request #11124 from wangjohn/removing_deprecated_rake_tasks

Removing deprecated rake tasks for tests
Move delegation error constant to inside Module
Review railties changelog [ci skip]