Fixed segfault when trying to paste partially copied (and thus erroneous) patch from an external source (e.g. a text editor) where the copied contents contain only "connect" instructions.

further fine-tuned the external buffer copy/paste logic to avoid redundant reloading of the clipboard

Added universal copy and paste allowing importing of patches by copying and pasting the text directly into the patch. Still need to decide whether auto-resizing of the window is also desirable (there are both pros and cons).