Expanded the bullet point syntax

* Removed the quote-by-line syntax, on the basis that a good number of
people don't really want indenting that often, and would rather have
greater-than signs as bullet points. The rest can rely on the indented
block syntax (<<<) or HTML.
* Expanded the bullet point syntax. Now, greater-than signs,
equals-signs, hyphens and two-character ASCII right-arrows (->, =>) can
be used to generate special bullet points.
* Removed <<set>>'s defaulting of object properties, due to
inconsistencies when setting multiple variables in one <<set>> tag.
* Nested <ul>s no longer have a margin-top.