Part of #1921152: META: Start providing tour tips for other core modules.
Problem/Motivation
Write tour integration for custom_block.module
Proposed resolution
Create tour yml files for required admin screens in custom_block.
Remaining tasks
Review custom_block_menu() and decide on screens that require tour integration
Write tour integration
User interface changes
New tours
API changes
None
Technical pointers when creating tour tips
See: https://drupal.org/node/1921152#tour-tips-tech-note for tech notes on making tour tips.