Commits on Apr 8, 2016

1. Use better JS engine defaults …

   This adds in preferences for all the SM 39 available options (as
   retrieved from Gecko), and uses the same defaults as Gecko. A few
   properties are not supported yet, and incremental GC is still always
   disabled regardless of the preference setting.
   
   This also adds back in the options that were accidentally deleted when
   \#10342 was rebased, which moved things from script_thread.rs to
   script_runtime.rs.

   

   metajack committed Apr 8, 2016

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