Enable cut-line support

I really like both packages so I'm determined to make them work together.  

The premise of cut-line is to copy the whole line when no selection is made.  Easy enough, but it gets a little trickier.  Another cool feature is: when you paste a "whole line" right after you copied it.  The paste should go below the current line instead of right where the cursor is.

To tell paste that the clipboard contents is a full line, cut-line adds some clipboard metadata.  I added this functionality to your copy method.  So I can use your package to copy and theirs to paste.

However, cutting a line is not implemented, I didn't see an easy way to add it.  Also, pasting from your package should paste on a new line, that is probably easier to add.

To override their copy, I had to make your keymap more specific than theirs by adding: `.workspace`.

```coffee
'.platform-linux .workspace .pane.active > .item-views > .editor':
  'ctrl-c': 'clipboard-history:copy'
```