bring back the markdown post feature (after investing some effort to make it work)

include/features.php

@@ -363,6 +363,15 @@ function get_features($filtered = true) {
 
 			t('Post/Comment Tools'),
 
+			[
+				'markdown',        
+				t('Markdown'),					
+				t('Use markdown for editing posts'),
+				false,
+				get_config('feature_lock','markdown'),
+				feature_level('markdown',2),
+			],
+
 			[
 				'commtag',        
 				t('Community Tagging'),					

include/markdown.php

@@ -49,14 +49,17 @@ function markdown_to_bb($s, $use_zrl = false, $options = []) {
 
 	$s = $x['text'];
 
-	// Escaping the hash tags - doesn't always seem to work
-	// $s = preg_replace('/\#([^\s\#])/','\\#$1',$s);
-	// This seems to work
+	// Escaping the hash tags
 	$s = preg_replace('/\#([^\s\#])/','#$1',$s);
 
 	$s = MarkdownExtra::defaultTransform($s);
 
-	$s = str_replace("\r","",$s);
+	if($options && $options['preserve_lf']) {
+		$s = str_replace(["\r","\n"],["",'<br>'],$s);
+	}
+	else {
+		$s = str_replace("\r","",$s);
+	}
 
 	$s = str_replace('&#35;','#',$s);
 

include/network.php

@@ -716,6 +716,10 @@ function scale_external_images($s, $include_link = true, $scale_replace = false)
 				$scaled = str_replace($scale_replace[0], $scale_replace[1], $mtch[3]);
 			else
 				$scaled = $mtch[3];
+
+			if(! strpbrk(substr($scaled,0,1),'zhfmt'))
+				continue;
+
 			$i = z_fetch_url($scaled,true);