Refactor Logic Around Blank Line Being Put Around Content

[pjkaufman]

This makes the empty line around content logic more robust and reusable.

Changes Made:

• Converted the logic over to get the start of the line ignoring non-whitespace and greater than characters (>)
• Made sure the logic would decide which empty line value to use when blockquotes were involved to make things more uniform
• Updated several examples to show the change in logic

[pjkaufman]

This was started on because it seemed related to #560 at the time. Now it is just more of an enhancement.