[Flurry Analytics] Update for 4.2.3 SDK (Security framework req. & bound new method for crash reporting) 

Flurry is requesting that devs update to version 4.2.3 of their SDK before iOS 7 comes out to "avoid compromising your user data in the move to iOS 7".  This version of the SDK appears to require the Security framework. More info: http://support.flurry.com/index.php?title=Analytics/FAQ/4.2.3_update

Version 4.2.3 of the SDK also includes the general availability of the new (optional) crash analytics feature.  I've bound the new SetCrashReportingEnabled method to allow access to this.

I noticed that Flurry is now including the SDK version number as part of the binary (eg. libFlurry_4.2.3.a).  You'll need to rename this to libFlurry.a prior to running make.

It's my first time attempting to contribute so please go easy on me if I'm doing something wrong.  :-)