Release candidate of TOhtml

Attached is a release candidate for the next update of the TOhtml
standard plugin distributed with the Vim runtime.

The major addition in this release is a new feature to specify areas
of text which do not get copied from a browser showing the rendered
page. Thus, you can copy-paste code from the browser without also
pasting line numbers, fold column, etc.

Please give it a try and reply to this thread (or to me) with any
issues you encounter. Next weekend, I will remove the "rc1" from the
version number and submit this to Bram otherwise unchanged, if there
are no major issues.

Here's the help text added for the new feature:

				*TOhtml-uncopyable-text* *g:html_prevent_copy*
Default: empty string.
This option prevents certain regions of the generated HTML from being copied,
when you select all text in document rendered in a browser and copy it. Useful
for allowing users to copy-paste only the source text even if a fold column or
line numbers are shown in the generated content. Specify regions to be
affected in this way as follows:
	f:	fold column
	n:	line numbers (also within fold text)
	t:	fold text
	d:	diff filler

Example, to make the fold column and line numbers uncopyable: >
	:let g:html_prevent_copy = "fn"
<