Added retry functions to attempt multiple assertions.
Added retry functions to attempt multiple assertions.

This is very handy when you don't want to hard-code timeouts in your
tests. Instead you can spin a few times on an assertion.

songxiang321/ios-monkey,alexvollmer/tuneup_js,giginet/tuneup_js,alexvollmer/tuneup_js,MYOB-Technology/tuneup_js,giginet/tuneup_js,Banno/tuneup_js,songxiang321/ios-monkey,MYOB-Technology/tuneup_js,misfitdavidl/tuneup_js,Northern01/tuneup_js,Northern01/tuneup_js,misfitdavidl/tuneup_js,Banno/tuneup_js