Idea: plugin to warn about improperly comparing hashes (sha1, etc)

[TysonAndre]

For hash_file, md5, sha1, etc.

• Override the return type in the plugin to be 'fake_hash_value_' . $i
• Warn if using != or == instead of ===. Loose inequality has surprising behaviors. (analyze in PostOrder with that plugin)
• Separately, suggest using hash_equals for hashes of sensitive information (passwords)