Use readFileSync and JSON parse to read config

I symlink my .csscomb.json file to another file that doesn’t have a
json extension. which causes node’s require to bork.

Author: jonrohan

lib/csscomb.js

@@ -225,7 +225,7 @@ CSScomb.getCustomConfig = function getCustomConfig(configPath) {
     configPath = configPath || CSScomb.getCustomConfigPath();
 
     try {
-        config = require(configPath);
+        config = JSON.parse(fs.readFileSync(configPath, 'utf8'));
     } catch (e) {
         config = null;
     }