require vs require_relative

[pointlessone]

A few issues has been submitted regarding use of require_relative in Prawn.

It's been some time since then so I'd like to revisit this but in a centralized manner. Please let me know if you still experience the issue or believe the change is warranted for any other reason.

Related PRs/issues:

• Use require_relative to prevent encoding.rb from being loaded twice #618 — instance of a split load
• Move all requires to top level and use require instead of require_relative #1013
• Warnings Prawn - PDF Core #1024
• replace require_relative in spec helper #1176
• Use require instead of require_relative pdf-core#29
• Warnings since update version 0.7.0 pdf-core#30
• Use require instead of require_relative pdf-core#33