fixed #2043: Upgrading SpiderMonkey to Firefox20.0.
Merge branch 'master' into iss2043-upgrade-spidermonkey20
fixed #2043: Disabled YARR_JIT on ios.
fixed #2043: Updating to spidermonkey20 for android.
fixed #2043: Updating spidermonkey to Firefox v20 for Windows.
Merge pull request #2357 from dumganhar/iss2043-upgrade-spidermonkey20

fixed #2043: Upgrading SpiderMonkey to Firefox20.0.