add osd message and use keybind in config file

eatit.lua

@@ -98,6 +98,7 @@ end
 -- start install
 local function startinstall()
   logwrite('Starting Download...')
+  mp.osd_message('Downloading plugins!')
   for i = 1, tablelength(plugins) do
     -- check if the user has defined a file for the current plugin
     if not plugins[i]['file'] then
@@ -177,4 +178,4 @@ os.remove(fn)
 closelog()
 
 runopts()
-mp.add_key_binding('U', 'UpdatePlugins', initupdate)
+mp.add_key_binding(opts.bind, 'UpdatePlugins', initupdate)