Fix rich text editor icons in Chrome

The links weren't clickable in Chrome using the text replacement method,
so just use I tags for the icon.  I don't really like this because it
seems un-semantic, but it's the way Font Awesome's docs recommend inserting
icons without acompanying text.

Addresses #231
Factor out explorer filter fancy tooltip creation
Hide tooltips when opening explorer filters

Addresses #320
Remove gradient from social login buttons in IE

The method for creating gradients in MSIE overflows the rounded corners
of the button and looks sort of weird. The most lightweight, easy
workaround is to remove the gradient effect in IE.

Re-closes #347.
Merge branch 'release' into develop
Merge branch '417_reload_hash_url' into develop
Backport of #558 workaround into release branch

I should have done 7ceefba2adee29b22d803cf7ad477c170370378f in a separate
branch.  To avoid some of the messyness of git cherry-pick, I'm just
explicitly making this change instead of cherry-picking the commit.
Merge branch 'release' into develop
Better test for title field

When I was doing manual tests, I ran into a case where the connected story
builder was loading, but with an empty form, not the existing story. The
automated integration tests now check for the story title in the title
input.

Addresses #417