try to use round avatars
Add AvatarWidget
Remove avatar-mask

We don't need it anymore with the new approach.
TweetListEntry: Use AvatarWidget
Revert "try to use round avatars"

This reverts commit 64d1faed801e4c8dac1ff3ef2ed133c3c962b620.

not needed anymore.
ProfilePage: Use AvatarWidget
TweetInfoPage: Use AvatarWidget
TweetInfoPage: Fix media clicked handler
MainWindow: Use AvatarWidget
MainWindow: Remove using statement

Slipped through my previous grep because it wasn't propertly indented.
Add 'round avatars' option

And remove the 'show inline media' one. it's not used anymore.
AvatarWidget: Respect the round-avatars setting
AvatarWidget: Use the border color for our custom border
style.css: style avatars
ComposeTweetWindow: Use AvatarWidget
tweet-list-entry: Fix the avatar's margin-top
Remove pic.twitter.com links from the tweet text
modify-filter-dialog: Fix untranslated title
tweet-list-entry: Add some margin-top to the text
Use a utility method for the (default) media clicked handler