#1397 Align event names

[Christian-Holbrook]

Resolves #1397

• Standardize the names for the plugin interface.
  • Use 'provide' instead of 'create'.
  • Use verbs before nouns.
  • Use 'remove' instead of 'dispose'
• Add before, current (which has no prefix), and after prefixes for most events.
• all old names were added to the plugin sanitizer to be upgraded gracefully (with warning) when possible.

[markwpearce]

I like the consistency of the naming.