css: Implement #sidebar and #mainContent without floats.

170aa38bb5c3972293846aa4d86540b4967effab fixed one bug but added another:
#mainContent would always be the max-width of 1000px. If the user's window
wasn't wide enough to accommodate that alongside the sidebar, it would be
rendered below the sidebar.

Fix that by using positioning instead of floats, so #mainContent can have a
flexible width.

js: Render <video> inner HTML when no source is supported.

The HTML inside <video> is meant to be rendered by browsers that don't
support the tag at all. You have to respond to the JavaScript error event
to deal with browsers that support video, but no available source. See
<https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Using_HTML5_audio_and_video#Showing_fallback_content_when_no_source_could_be_decoded>;.

css: Remove unused rules.

The rationale given in the comments for these rules no longer applies: there
are no divs with class column or conservancy-blog on any pages. Meanwhile,
they're causing unwanted styling: we started using the column class on the
front page for two-column layout, and the videos are appearing smaller than
desired there. Just remove these.

blog: Headlines clear floats.

This avoids a situation where multiple summaries have floats that stack on
top of each other vertically, which end up getting far away from the actual
text.

In order to make this work, we had to change the styling of #mainContent on
blog pages (and others with a sidebar). Otherwise, headlines with
class="clear" would clear the sidebar as well.

blog: Refactor entry rendering into a partial.

This helps ensure that entries are rendered consistently wherever they
appear.

css: Remove noop rule.

This wasn't doing anything because "line-height" was misspelled.

css: Start a separate stylesheet for "big screen" styles.

I'm about to add more and I *suspect* this will be easier to maintain
in the long term, rather than duplicating the conditional many times.

frontpage: Reduce the two-column width split to 67em.

This brings the columns from a target width of about 60 characters to
about 52.

frontpage: Reorganize.

* Put news and blogs up front.
* Use 30 days as the cutoff for everything, consistently.
* Allow columns to collapse. Hopefully this is the start of a nicer
view on mobile.
* Reduce shading.

Rename Members->Projects in menu navigation et al

Due to confusion about "members" and "supporters", we want at least the
menu navigation to not use the phrase "members" since some Supporters
expect that to refer to a type of donor.

While we will not be rebranding "member projects" fully at this time, we
want to favor the term projects.

A few additional changes, in particular moving files from members/ ->
projects/ directory will be needed in next commit.

Supporter page: Refactor JavaScript.

This isn't intended to have any functional change, it's just DRYing up
the code to simplify functional changes later.

Remove problematic four digit CSS code

Text is not dislpayed correctly with newer browsers, such as Firefox 49,
because of CSS color values. In current browsers the four digit values
are discarded as invalid CSS. Browsers are adding support for RGBA as a
valid CSS color value.

https://github.com/webcompat/web-bugs/issues/2628

Move from #mainContent to #container #mainContent

A few adjustments as well.

More suggestions from j-b.

<j-b> and also fixed the background from #fffff; to #ffffff;

Improvements suggested by j-b on IRC.

I didn't take all his suggestions, but a few.

Fix gradients broken by previous commit.

[0d89044: Replace gradient images with CSS gradients.] replaced gradient
images with CSS gradients but in doing so changed some of them from
light blue to gold. Change the colours to correct ones where necessary.

[PATCH 1/2] Fix unnucessary horizontal scroll bar; simplify header markup.

Because #logobutton had a fixed width, browser window narrower than 933
pixels resulted in an unnecessary horizontal scroll bar. Fix that by
using a dynamic 100% width which results in the header image being
automatically clipped as necessary.

To avoid clipping the tree and the text though, include min-width so
that very narrow windows result in a horizontal scroll bar so the whole
name can be seen.

Furthermore, simplify the markup by removing wrapper DIV and SPAN
elements which weren’t really necessary. As a consequence of that
change, the whole top of the page is now a link to the homepage (i.e.
‘/’). Prior to this change, the link wasn’t clickable.

Add legacy support for older firefox/iceweasel.

In this situation:

<body class="conservancy-blog">
...
<video>

it turned out that this CSS:

body.conservancy-blog video {}

Did not apply.

So, this adds a hack to force the issue.

Attempt to improve fonts.

I noticed after I updated to jessie that fonts displayed strangely in
some browsers. I still have strange fonts on our website with Chromium,
but this change seems to have helped iceweasel.

site-wide supporter count fundraiser.

Using the jQuery UI multiprogress bar added earlier, this change allows
display of the of the progress bar on every page.