Update _dark.sass
Merge pull request #157 from mimi89999/patch-2

Update _dark.sass
fix #154, all covers get loaded now

I mentioned this before because original code change is not good enough.
Checking from console, some soundCloud videos would return empty cover
and in that case, we can't refer to our defaultImage, sad.
Merge pull request #158 from EragonJ/bug/154

fix #154, all covers get loaded now
Added remove from history button
Language is now saved between sessions
Window location is now saved between sessions
remove redundant semicolon
add notification support
Merge pull request #162 from EragonJ/feature/add-notification

add notification support