Feature Request: Scheduled Content; No Expiration Option and Button for the Text Editor

The title pretty much says it all. I believe it would be useful to have an option to omit the "length" attribute from Scheduled Content's shortcode to enable the scheduled release of content for which no expiration date is required/desired.

Additionally, it would be helpful to have a button in the Text Editor, for those who prefer to avoid the Visual Editor and its tendency to destroy formatting.