Removed notice about undefined variable.
Removed notice about undefined variable.

MWDelaney/bootstrap-3-shortcodes,filipstefansson/bootstrap-3-shortcodes,n054/php-markdown,robbieaverill/php-markdown,MWDelaney/bootstrap-3-shortcodes,queirozfcom/php-markdown-with-syntax-highlight,Kapeli/php-markdown,jockchou/php-markdown,ashur/php-markdown,MWDelaney/bootstrap-3-shortcodes,mariokonrad/php-markdown,filipstefansson/bootstrap-3-shortcodes