Adds support for syntax highlighting and formatting both ordered and
unordered lists (excluding unordered lists delimited with `*`, as they
conflict with headings and are generally not recommended).
e.g.
1. Foo
2. Bar
1) Biz
2) Baz
- Foo
- Bar
+ Biz
+ Baz
Previously the following would've caused everything after the `/` to be
italicised (until it found a second `/`).
foo/bar
The same happened with all of the other in-line delimiters. This was
clearly not good enough.
The new in-line delimiter matching is now much closer to Emacs' than
before while maintaining Unicode support (as well as Vim can offer).
- Fixes issues with Vim's spell checker not spell checking regular text
in Org-mode files.
- Disables the use of italic fonts by default (an option is now
provided to change this behaviour).
- Disabled conceal for all elements except hyperlinks.
- Concealed elements are now only unconcealed when editing the text.
- Re-organised blocks in the syntax file.
