Disable "smart" undo? #95
Description
I believe this might have been brought up in #11, but the code it references was lost in the GoogleCode export. The markdown editor's undo behaves differently than standard text editors', particularly when pasting a markdown operator. For example, if I copy ** and paste it multiple times into the document in different positions, then hit ctrl+z, all instances of the ** are removed from the document.
This is inconsistent with standard text editors, which will remove the last instance of ** from the paste action.