Moved rules into their own files

Everything under `lib/rules/*` is a rules file (with the name of the rule in camelCase), re-exported into an array in `lib/rules.js`.
Moved the regular expressions from `lib/rules.js` to `lib/expressions.js`, and the rest of the variables into `lib/shared.js`.

lib/rules/properNames.js

@@ -0,0 +1,44 @@
+var shared = require("../shared");
+var expressions = require("../expressions");
+
+module.exports = {
+  "name": "MD044",
+  "desc": "Proper names should have the correct capitalization",
+  "tags": [ "spelling" ],
+  "aliases": [ "proper-names" ],
+  "regexp": null,
+  "func": function MD044(params, errors) {
+    var names = params.options.names || [];
+    var codeBlocks = params.options.code_blocks;
+    var includeCodeBlocks = (codeBlocks === undefined) ? true : !!codeBlocks;
+    names.forEach(function forName(name) {
+      var escapedName = shared.escapeForRegExp(name);
+      var namePattern = "\\S*\\b(" + escapedName + ")\\b\\S*";
+      var anyNameRe = new RegExp(namePattern, "gi");
+      function forToken(token) {
+        var fenceOffset = (token.type === "fence") ? 1 : 0;
+        token.content.split(shared.newLineRe)
+          .forEach(function forLine(line, index) {
+            var match = null;
+            while ((match = anyNameRe.exec(line)) !== null) {
+              var fullMatch = match[0];
+              if (!expressions.bareUrlRe.test(fullMatch)) {
+                var wordMatch = fullMatch
+                  .replace(/^\W*/, "").replace(/\W*$/, "");
+                if (names.indexOf(wordMatch) === -1) {
+                  var lineNumber = token.lineNumber + index + fenceOffset;
+                  errors.addDetailIf(lineNumber, name, match[1]);
+                }
+              }
+            }
+          });
+      }
+      shared.forEachInlineChild(params, "text", forToken);
+      if (includeCodeBlocks) {
+        shared.forEachInlineChild(params, "code_inline", forToken);
+        shared.filterTokens(params, "code_block", forToken);
+        shared.filterTokens(params, "fence", forToken);
+      }
+    });
+  }
+};