Replaced the sentinal-based doubly-linked list implementation in Outline.js with one that uses first and last pointers instead. This is slightly simpler to iterate through because you can simply start with the first item and use a null check as the terminating condition.
Replaced the sentinal-based doubly-linked list implementation in Outline.js with one
that uses first and last pointers instead. This is slightly simpler to iterate through
because you can simply start with the first item and use a null check as the terminating
condition.

corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editor,corinthia/corinthia-editorlib,corinthia/corinthia-editorlib