Kellyroach/upgrade to xcode941

[kellyroach]

This pull request upgrades FRD3DBarChart to Xcode 9.4.1 .
Currently, in master branch out of the box, FRD3DBarChart gets 3 red build errors relating
to glBindVertexArrayOES which can be cured by adding an "#import <OpenGLES/ES2/glext.h>".

Our pull request does the following:

• Add '#import <OpenGLES/ES2/glext.h>' to restore compilation
• fabs in 3 locations to elminate compiler warnings
• Xcode 9.4.1 update to recommended settings
• Fix Analyze 'Dead store', 'Memory' leak, and 'Logic error' warnings
• NSDate * --> CFAbsoluteTime in FRD3DBarChartViewController.m
• Remove viewDidUnload is deprecated
• Remove unnecessary didReceiveMemoryWarning implementation
• Remove shouldAutorotateToInterfaceOrientation: is deprecated
• Upgrade to Xcode 9.4.1 project, *.storyboard, and InfoViewController.m+.h
• Add AppIcon and dark LaunchScreen