Improved nimdoc styling.

This updates the inlined CSS in nimdoc.cfg, adds several helper classes
(and a few divs) to the generated HTML (some in nimdoc.cfg, one in
rstgen.nim), and tweaks the anchor linking scheme for headers in
rstgen.nim.
Update nimweb.nim to work w/ non-hardcoded --docSeeSrcUrl argument to nim doc
fixed typos so docgen works again
Merge branch 'devel' of https://github.com/Araq/Nimrod into devel
Merge pull request #1748 from boydgreenfield/improved-doc-styling

Improved doc styling
cleaned up os.nim; docgen improvements
better CSS; better docs for teh tables module
Fixes #1759.

Caused by not skipping the \c\l with Chunked encoding after the body is parsed.
Fix source code links
Fix blockquotes in documentation; stylize only in docinfo or immediately after an h1
Logo in SVG format.

This has been created using Inkscape, starting from a .png file created
by @PhilipWitte (see
http://reign-studios.net/philipwitte/nimrod/new-symbols.png, the third
icon from left in the top row).
Fix paragraph break issue in nimc.txt. Add spacing to command line options table.
Remove TOC from gc.txt, but get quote at top properly formatted
Removed extra line breaks from unittest output.
Update installation instruction
Merge pull request #1763 from ziotom78/devel

Logo in SVG format.
Merge pull request #1764 from boydgreenfield/further_doc_fixes

Further doc fixes
Merge pull request #1766 from gmpreussner/devel

Removed extra line breaks from unittest output.
Merge pull request #1767 from sanxiyn/patch-1

Update installation instruction
website updated