Remove the marker line from the drop target.
Remove the marker line from the drop target.

Now drag and drop doesn't silently fail when dropping exactly between two nodes.

fixes #95

adam3smith/csl-editor,citation-style-editor/csl-editor,citation-style-language/csl-editor,fbennett/csl-editor,citation-style-language/csl-editor,adam3smith/csl-editor,citation-style-language/csl-editor,citation-style-editor/csl-editor,fbennett/csl-editor,adam3smith/csl-editor,citation-style-editor/csl-editor