Issue #2783929 by gaurav.goyal, Jitujain: Error moving files

• Fixes #2598260: Placeholder option missing
• Fixes #2792753: $errors array variable should be declare before setting value or returning it

Issue #2797059 by sanduhrs: Fix array keys in render array
Revert "Issue #2797041 by sanduhrs: Use non-magic method to get value from field"
Issue #2797053 by sanduhrs: Remove unused blanko template
Issue #2797051 by sanduhrs: Update EAN13 template to slice the code into pieces
Issue #2797045 by sanduhrs: Move code outside try/catch block
Issue #2797041 by sanduhrs: Use non-magic method to get value from field
Issue #2797037 by sanduhrs: Value not defined in default block configuration
Issue #2797033 by sanduhrs: Add libraries and styles

Various bug fixes and small improvements, see full release notes for details.

Issue #2710155 by szeidler, rachel_norfolk, marcoh182, TechnoTim2010, Patrick Ryan: Drupal 8 support

Maps are now working on Drupal 8 without the need to manually install zip files. The demo module is currently *not* functioning and needs a overhaul before we release a beta and, finally, a full release.

Fix critical bug that prevented language header language negotiation