excertp is up to first double newline, fix title replacement regex

Author: roborourke

inc/class-importer.php

@@ -296,17 +296,17 @@ protected function update_post_from_markdown_source( $post_id ) {
 $title = null;
 if ( preg_match( '/^\n*#\s([^\n]+)/', $markdown, $matches ) ) {
 $title = $matches[1];
-$markdown = preg_replace( '/^\n*#\s([\n]+)/', '', $markdown );
+$markdown = preg_replace( '/^\n*#\s([^\n]+)/', '', $markdown );
 }
 // Allow YAML override.
 if ( isset( $yaml['title'] ) ) {
 $title = $yaml['title'];
 }
 $markdown = trim( $markdown );
 
-// Steal the first sentence as the excerpt
+// Steal the first paragraph as the excerpt
 $excerpt = '';
-if ( preg_match( '/^([^\.]+)[\s$]/m', $markdown, $matches ) ) {
+if ( preg_match( '/^(.*?)\n\n/', $markdown, $matches ) ) {
 $excerpt = $matches[1];
 }