Add 'figure' to list of block-level elements in _MarkdownExtra_TmpImpl
Add 'figure' to list of block-level elements in _MarkdownExtra_TmpImpl

ashur/php-markdown,mariokonrad/php-markdown,n054/php-markdown,jockchou/php-markdown,queirozfcom/php-markdown-with-syntax-highlight,robbieaverill/php-markdown,Kapeli/php-markdown