Fix bug of the pidFile mechanism.

1. Cleanup should be called at the end instead of start.
   Since it'll remove the pidFile we just created.

2. Unlock must come after unlink or we'll suffer race condition.
   EX: procA launched -> procA process -> procA unlock ->
       procB launched -> procA unlink
   Oops, procA remove procB's pidFile...

3. We must open pidFile with os.open + os.fdopen or the pidFile
   will be truncated even if our netgui is still running.
   It won't cause any problem now, however, it's a potential bug.
Call cleanup whatever happened
Make treeview scrollable in case there's lots of ap.
change the way of checking whether network is connected
fix of potential bug (prefix need not to be "netgui_")
Bugfix of CreateConfig ... Orz
Merge pull request #6 from coquelicot/develop

Fix bug of the pidFile mechanism / Scrollable network list / Creating Profile.