Add stats from last perf run

stats.md

@@ -0,0 +1,49 @@
+## Performance Stats
+
+#### drupal (-27%)
+```
+old parser: 42.2
+new parser: 30.8
+```
+
+#### wordpress (-33%)
+```
+old parser: 3.6
+new parser: 2.4
+```
+
+#### php-language-server (-17%)
+```
+old parser: 13.3
+new parser: 11.0
+```
+
+#### tolerant-php-parser (+59%)
+```
+old parser: 3.7
+new parser: 5.9
+```
+
+#### math-php (-35%)
+```
+old parser: 1.7
+new parser: 1.1
+```
+
+#### symfony (-23%)
+```
+old parser: 18.2 
+new parser: 14.1
+```
+
+#### CodeIgniter (-23%)
+```
+old parser: 1.8
+new parser: 1.1
+```
+
+#### cakephp (-24%)
+```
+old parser: 5.1
+new parser: 3.9
+```