Version 6.1.0

Changes

• Add remove_constraint_url [Justin Coyne]
• Rename the generated blacklight.css.scss file to blacklight.scss to
  match modern conventions [Chris Beer]
• Add skip-assets flag to the install generator [Chris Beer]
• Address bug in default template install process (Solr4Generator). [Jessie Keck]
• Remove generation of globalid gem [Justin Coyne]
• Fix documentation typo [Justin Coyne]
• Remove .rubocop_hound.yml and address some basic rubocop violations
  [Chris Beer]
• Remove unused ZIP_URL from blacklight's rake tasks [Chris Beer]
• Fix exception handling [Chris Beer]
• Use i18n to provide a default title in an email [Chris Beer]
• Address rubocop lint [Chris Beer]
• Loosen rsolr dependency restriction to support rsolr 1.1 [Chris
  Beer]
• Clean up the template so that it uses good style [Justin Coyne]
• Test with Rails 5 beta 3 [Justin Coyne]