0.23.0/project-overview-formatting

Purpose
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Fix https://trello.com/c/qqGZBAq5 - HGrid rows on project overview were not all displaying properly.

Was:
![screen shot 2014-12-30 at 9 31 02 am](https://cloud.githubusercontent.com/assets/6599111/5579324/a3bbd940-9006-11e4-8ee5-98a64cff3a59.png)

Now:
![screen shot 2014-12-30 at 9 30 31 am](https://cloud.githubusercontent.com/assets/6599111/5579334/ab3e8a46-9006-11e4-8262-fc5d5e31a80d.png)

Changes
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Img elements in the project overview hgrid broke the hgrid display when they had the block format applied to them, so I separated out the wiki and addon-widget-container classes to be slightly different. Wiki images are still block elements, but addon-widget-container images are not.

Side effects
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According to the comment, one of the goals of the wiki img formatting was to make the images more responsive, so possibly I broke that, but I tested with the image above, and it seemed to work at various page widths, so it should be fine. That being said, maybe more complex wiki image views?