Some changes to code views in hgweb

[Jordi Gutiérrez Hermoso]

There are two things I don't like about hgweb's code views:

1) When trying to select code for pasting, you also get lines of code.
I would like to disable that like like this:

    http://stackoverflow.com/questions/826782/css-rule-to-disable-text-selection-highlighting

Is it acceptable to use prefixed CSS rules in hgweb?

2) The stripes are jarring and conflict with some Pygments styles. Can
we get rid of stripes for code views? The stripes make more sense for
lists of similar-looking data such as revisions, but I don't like them
for code views, and hg is rather unique out there for using stripes
for code views.

- Jordi G. H.