[Sparkle] Support for custom version comparator?

[Jeff Johnson]

Hi. We have a custom version comparator that we'd like to use for our  
apps. Would it be possible to add support for custom comparators to  
Sparkle?

One possible implementation would be to add a versionComparator  
method to both SUUpdater and SUUpdaterDelegateInformalProtocol.  - 
[SUUpdater versionComparator] would check [[self delegate]  
versionComparator] and return the result if non-nil, otherwise it  
would return [SUStandardVersionComparator defaultComparator]. Then  
the calls to [SUStandardVersionComparator defaultComparator] in  
SUBasicUpdateDriver.m could be replaced with [[SUUpdater  
sharedUpdater] versionComparator]. This would allow the delegate to  
provide a custom version comparator.

We can submit a patch for this functionality, so please let me know  
whether it's feasible and whether the implementation is appropriate.  
We could also try a different implementation instead, if you have  
other suggestions. Thanks!

-Jeff Johnson