Rewrite ConditionalBindingCascadeRule

[norio-nomura]

• Fix Conditional binding cascade rule does not work #617
• Add ASTBaseRule
ASTBaseRule takes kind as String for supporting other than SwiftDeclarationKind.
  ASTRule inherits ASTBaseRule.

[norio-nomura]

Updated.

• Add false negative example to ConditionalBindingCascadeRule from Conditional binding cascade rule does not work #617
• Add changelog entry

[norio-nomura]

make sum_test fails randomly on both Travis-CI and local mac.
We need to update SourceKitten in Package.swift, but I won't update it in this PR.

[jpsim]

This is the wrong url

[jpsim]

👍 other than where noted

[norio-nomura]

Performance note:
The duration of ConditionalBindingCascadeRule on linting Carthage-16.2 increased from 64ms (w/ 62c7d4a) to 283ms (w/ d3f698f).

[jpsim]

Looks great to me, thanks!

[norio-nomura]

Thanks for reviews and merging! 🙏