Rename golden files for easier tracking.

Implement trimming spaces at end of lines.

Make paragraphRect origin always 0,0.

This convention should make it easier for the caller to properly place
the paragraph within a document.

Add ignored prefixes and suffixes to test data.

This ensures that implementation does not rely on the texts having zero
offset inside their byte arrays.

Use ICU to find line break boundaries.

Implement line breaking on code point boundaries.