Feature: Allow preference to make adding a tab to the current window a default behavior

[prodigitalson]

Similar to a browser or Sublime-like text editor, allow for files to be opened as tabs in an existing window. Currently you can gather windows, or you can manually open a new editor in a window as a tab, but there is no way to make this the default behavior. Additionally it would be nice to File > New in Tab and File > New in Window selections with the common hot keys Shift+CMD|CTRL+N and CMD|CTRL+N.