fixes #940

fix rubocop bugs
Merge pull request #942 from fshowalter/fix_940

fix useless_access_modifier bug
Minor changelog change
Enhance NegatedIf and NegatedWhile

They now handle properly `unless` and `until` constructs.
[Fix #925] Don't disable Syntax cop in rubocop-todo.yml

The Syntax cop is a fake cop and it can't be disabled in configuration.
Merge pull request #941 from jonas054/fix_auto_gen_config_syntax_cop

[Fix #925] Don't disable Syntax cop in rubocop-todo.yml
Fix changelog entries
[Fix #943] Fix auto-correct interference with SpaceAfterComma

The SpaceAfterComma (and possibly other cops that include
SpaceAfterPunctuation) can destroy code if other cops are auto-
correcting in the same area. The solution is to make a bigger
substitution, so conflict resolution logic kicks in.
Merge pull request #951 from jonas054/fix_943_autocorrect

[Fix #943] Fix auto-correct interference with SpaceAfterComma
failing test case for NilComparison autocorrect
[Fix #954] Auto-correct `x === nil` in NilComparison
failing test case for NonNilCheck
[Fix #953] Auto-correct properly code like `!nil?` in NonNilCheck
Add failing test case for StringConversionInInterpolation
[Fix #952] Handle implicit receiver in StringConversionInInterpolation
proper failing test case for ClassMethods
[Fix #956] Apply ClassMethods check only on class/module bodies
Fix SpaceBeforeFirstArg cop for multiline argument

and exclude assignments