Added buffer auto-close functionality on swapfile event

[amygara]

Since I drive my environment with buffers/splits, I wanted to keep my buffer bar uncluttered. By default when a swap was open in a remote instance, the buffer bar tab would stay open and be inaccessible to edit or close. This adds a variable that, when enabled, will auto-close the local buffer who's swapfile was already opened by a remote instance. Sorry for the PR on a very old repo xD