Merge pull request #2100 from RosettaCommons/roccomoretti/RosettaScripts_empty_sfxn
A few small, unrelated administrative changes.
* Tell git to ignore the DAlphaBall executable if it's built (in main/source/external/DAlpahBall/)
* Update the naive/default runtimes for integration tests.
This was originally going to add "empty" to the list of pre-defined scorefunctions in RosettaScripts -- I dropped that plan, as it conflicts with the manual definition of "empty" within the XML, which a number of scripts are using.