Partially revert "Don't intersperse comments with metadata headers."

This reverts part of commit 983df5453d54214fd4153b89c60de9e316512e46.

Conflicts:
	webvtt.html
Partially revert "Introduce the concept of WebVTT metadata headers."

This reverts part of commit b82c0c5cce22d3bc7ae80087e2add3d6165b3564.

Conflicts:
	webvtt.html
Revert "Fix typo for region inclusion into cue settings."

This reverts commit f3bcb99c0d78812e9a28474003a4c62fd49c89a5.
Partially revert "Introduce regions into the WebVTT file syntax."

This reverts part of commit 02d95ce2a0833d6bdaaf02598fa42601e27b2847.

Conflicts:
	webvtt.html
Revert "Added region example to Introduction section under "Other features"."

This reverts commit 4255ed479aab5651654e323fd6e52915f951663c.

Conflicts:
	webvtt.html
Restore definitions (they are gone on master)
Restore line wrapping changes
Restore whitespace changes
Restore section heading changes
Restore CSS settings reformatting
Restore new sections