#5 Parser doesn't recognize overlines

[Sam Hartsfield]

ReST Editor seems to be recognizing overlined and underlined headings as the same as underlined-only heading with the same character. For example:

====
Head
====

is seen as the same as:

Head

However, they should be different. From the docs: "Underline-only adornment styles are distinct from overline-and-underline styles that use the same character." This bug screws up the outline and its movement features for documents that use this markup.

Reference: http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html#sections

[Thomas Calmant]

Fixed in hotfixes branch.

Will be released after some tests