use more threads to query game servers

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given the few seconds required to fetch all data from each game server, use of 
threads speeds up the overall update process.

Current code uses 10 threads only.

Attached patch allows to use more.
Details :
 - add "Misc Options" to the "Settings" tab
 - add "number of query threads" SpinButton on the "Misc Options" section
 - read/write the "number of query threads" value to config file with sanity checks (default value is 10)
 - when querying game servers, will now use up to "number of query threads" threads if and only if there are more than "number of query threads" game servers to query
 - fix misuse of threading.RLock() in the querymanager module (which fixes issues with geopip and threadcount that are more likely to arise with lots of concurrent threads) 

Original issue reported on code.google.com by thomasle...@gmail.com on 22 Oct 2011 at 12:15

Attachments:

• add-a-setting-to-set-the-number-of-threads-to-use-fo.patch