* bump eslint plugin to 0.5.2 Signed-off-by: Kerry Archibald <kerrya@element.io> * add rule Signed-off-by: Kerry Archibald <kerrya@element.io> * add missing copyright headers Signed-off-by: Kerry Archibald <kerrya@element.io> * fix comment order Signed-off-by: Kerry Archibald <kerrya@element.io>