Pass plugin's folder to plugin_start()

PLUGINS.md

@@ -22,11 +22,11 @@ Plugins are python files. The plugin folder must have a file named `load.py` tha
 EDMC will import the `load.py` file as a module and then call the `plugin_start()` function.
 
 ```python
-def plugin_start():
+def plugin_start(plugin_dir):
    """
    Load this plugin into EDMC
    """
-   print "I am loaded!"
+   print "I am loaded! My plugin folder is {}".format(plugin_dir.encode("utf-8"))
    return "Test"
 ```
 

plug.py

@@ -83,7 +83,10 @@ class Plugin(object):
             with open(loadfile, 'rb') as plugfile:
                 module = imp.load_module('plugin_%s' % name.encode('ascii', 'replace').replace('.', '_'), plugfile, loadfile.encode(sys.getfilesystemencoding()),
                                          ('.py', 'r', imp.PY_SOURCE))
-                newname = module.plugin_start()
+                if module.plugin_start.func_code.co_argcount == 0:
+                    newname = module.plugin_start()
+                else:
+                    newname = module.plugin_start(os.path.dirname(loadfile))
                 self.name = newname and unicode(newname) or name
                 self.module = module
         else: