Cleaned-up paste from external text into canvas feature, enabled the said paste action, and added ability to relocate and resize canvas as part of pasting into an empty canvas. If pasting into a canvas already populated with at least one object, the paste of the said information ignores canvas properties and pastes objects at mouse

and even more cleanup (make distclean before committing)... still trying to figure out this git thingy...

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).