Fixed issue with rescanning a new QR Code.

KNOWN ISSUES:
Issues
An exception is seen in the ChildDetailsViewController after rescanning a new QR code.

2013-10-27 12:19:10.022 Vaccinations[2217:60b] Record found. Loading fields
2013-10-27 12:20:11.894 Vaccinations[2217:60b] -[__NSCFString actionForLayer:forKey:]: unrecognized selector sent to instance 0x16ecb160
2013-10-27 12:20:11.897 Vaccinations[2217:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString actionForLayer:forKey:]: unrecognized selector sent to instance 0x16ecb160'
*** First throw call stack:
(0x305c4f4b 0x3ad336af 0x305c88e7 0x305c71cb 0x305164d8 0x329be3c7 0x329b85a9 0x329b854d 0x329b854d 0x329bd9c7 0x329be831 0x329be7bf 0x32d437dd 0x32d59aa5 0x32f0bbe9 0x32d496e5 0x32f0b479 0x32ec8ba7 0x32de6273 0x32de607d 0x32de6015 0x32d37da3 0x329bec6b 0x329ba47b 0x329ba30d 0x329b9d1f 0x329b9b2f 0x329b385d 0x305901cd 0x3058db71 0x3058deb3 0x304f8c27 0x304f8a0b 0x351ec283 0x32d9c049 0x46d29 0x3b23bab7)
libc++abi.dylib: terminating with uncaught exception of type NSException

Search for patient uncaught exception

2013-10-27 12:29:19.467 Vaccinations[2234:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'data parameter is nil'
*** First throw call stack:
(0x305c4f4b 0x3ad336af 0x305c4e8d 0x30f4ca6b 0x4ecef 0x4f0b5 0x32d6c713 0x32d6c6b3 0x32d6c691 0x32d5811f 0x32d6c107 0x32d6bdd9 0x32d66e65 0x32d3c79d 0x32d3afa3 0x30590183 0x3058f653 0x3058de47 0x304f8c27 0x304f8a0b 0x351ec283 0x32d9c049 0x4dd29 0x3b23bab7)
libc++abi.dylib: terminating with uncaught exception of type NSException
Added code to ScanViewController for Photo Library and Take Photo features.

KNOWN ISSUES:
Repeatedly switching from UINavigationController to UITabBarController will cause an exception.  There may be an inherent problem with the design as the UIBarTabController is not the root window per Apple’s design guide.
Merge remote-tracking branch 'origin/master'