fix #1606 broken markdown snippets

lib/ace/snippets.js

@@ -155,11 +155,13 @@ var SnippetManager = function() {
             case "SELECTED_TEXT":
                 return s.getTextRange(r);
             case "CURRENT_LINE":
-                return s.getLine(e.getCursorPosition().row);
+                return s.getLine(editor.getCursorPosition().row);
+            case "PREV_LINE": // not possible in textmate
+                return s.getLine(editor.getCursorPosition().row - 1);
             case "LINE_INDEX":
-                return e.getCursorPosition().column;
+                return editor.getCursorPosition().column;
             case "LINE_NUMBER":
-                return e.getCursorPosition().row + 1;
+                return editor.getCursorPosition().row + 1;
             case "SOFT_TABS":
                 return s.getUseSoftTabs() ? "YES" : "NO";
             case "TAB_SIZE":

lib/ace/snippets/markdown.snippets

@@ -23,14 +23,15 @@ snippet ![:*
 	![${1:id}]: ${2:`@*`} "${3:title}"
 
 snippet ===
-	`repeat('=', strlen(getline(line(".") - 1)))`
+regex /^/=+/=*//
+	${PREV_LINE/./=/g}
 	
-	${1}
+	${0}
 snippet ---
-	`repeat('-', strlen(getline(line(".") - 1)))`
+regex /^/-+/-*//
+	${PREV_LINE/./-/g}
 	
-	${1}
-
+	${0}
 snippet blockquote
 	{% blockquote %}
 	${1:quote}