Use new pattern style

Avoid a depreciation warning:

Warning: Deprecated pattern style '.../vendor/**' in .../config/default.yml. Change to '.../vendor/**/*'."
Merge pull request #1091 from Dorian/patch-1

Use new pattern style
Cleanup specs

* use described_class
* do not use instance variables
* do not start example description with should
[Fixes #1094] Fix bug in ClassAndModuleChildren

ClassAndModuleChildren incorrectly flaged class with a single method
Merge pull request #1095 from geniou/rspec_cleanup

Cleanup specs
Merge pull request #1096 from geniou/class_and_module_children_single_method

[Fixes #1094] Fix bug in ClassAndModuleChildren
Fix incorrect error message about rubocop-todo.yml
Merge pull request #1098 from agrimm/todo_filename

Fix incorrect error message about rubocop-todo.yml
[Fix #1089] Add -F/--fail-fast option

Inspect files in order of modification time, newest first. And stop after the first file with offenses.