WebServer: switch to HTML5.
Use font-size:0 for #seekbar td.

This fixes a visible white line showing below the seekbar.
Add normalize.css trimmed down to our needs.
Use Arial font and remove the inherited font from a couple places.
player.html is valid html5.

Note that seekbarchleft and seekbarchright width is set via js.
Use pre for the debug section.
browser.html is valid HTML5.
web/info.html: document where the mpchc_np id is used.
Tweak statusbar and menu td.
Cleanup and rename classes.
Update controls.html.

* use lowercase method "post"
* make the reloadenabled checkbox centered
* move inline style to default.css
WebServer.cpp: no caching for css files.