shortcode columns, replace prev

twocolumn (7 errors)
"posts\\24\\l\\44-two-col-res-code.md"
"posts\\24\\l\\43-two-col-md-eqn-code.md"
"posts\\24\\l\\42-two-col-code-result.md" 
"posts\\24\\l\\41-two-col-scatter-flowchart.md" 
"posts\\24\\l\\40-two-col-flowchart-md.md"
"posts\\24\\l\\39-two-col-scatter-md.md"
"posts\\24\\l\\38-two-col-md-eqn.md"

column-left, column-right (4 errors)
"posts\\25\\b\\22-outline-dummy-talk.md"
"posts\\25\\a\\36-bool-vs-fuzzy.md"
"posts\\25\\a\\20-llama-6-meeting.md"
"posts\\25\\a\\13-list-of-rusn_slides.md"