Add MD012, MD028 with tests, support multiple markers by line.

lib/rules.js

@@ -212,6 +212,45 @@ module.exports = [
     }
   },
 
+  {
+    "name": "MD012",
+    "desc": "Multiple consecutive blank lines",
+    "func": function MD012(params, errors) {
+      var exclusions = [];
+      params.tokens.filter(function filterToken(token) {
+        return ((token.type === "code_block") || (token.type === "fence"));
+      }).forEach(function forToken(token) {
+        for (var i = token.lines[0] ; i < token.lines[1] ; i++) {
+          exclusions.push(i);
+        }
+      });
+      var prevLine = "-";
+      params.lines.forEach(function forLine(line, lineIndex) {
+        line = line.trim();
+        if (!line.length && !prevLine.length &&
+            (exclusions.indexOf(lineIndex) === -1)) {
+          errors.push(lineIndex + 1);
+        }
+        prevLine = line;
+      });
+    }
+  },
+
+  {
+    "name": "MD028",
+    "desc": "Blank line inside blockquote",
+    "func": function MD028(params, errors) {
+      var prevToken = {};
+      params.tokens.forEach(function forToken(token) {
+        if ((token.type === "blockquote_open") &&
+            (prevToken.type === "blockquote_close")) {
+          errors.push(token.lineNumber - 1);
+        }
+        prevToken = token;
+      });
+    }
+  },
+
   {
     "name": "MD031",
     "desc": "Fenced code blocks should be surrounded by blank lines",