Refactor IAP Transport / Fix EASessions left open

[kmicha19-ford]

Fixes #1799 (when used in conjunction with kmicha19-ford#2)
Fixes #1809
Fixes #1892
Fixes #1893

This PR is ready for review.

Risk

This PR makes no API changes.

Testing Plan

• I have verified that I have not introduced new warnings in this PR (or explain why below)
• I have tested this PR against Core and verified behavior.

Unit Tests

Unit tests were updated for the refactored classes.

Core Tests

• Built the Obj-C example app and verified that all interactions work
  • iAP disconnect / reconnect
  • LockScreen on/off rapidly
• Built the Swift example app and verified that all interactions work
  • iAP disconnect / reconnect
  • LockScreen on/off rapidly

Summary

• Refactors iAPSession code that uses the Apple External Accessory Frameworks to create, open, use, and close EASessions.

Changelog

Breaking Changes

• None

Enhancements

• Moves all managment of EASession creation, open, and closing into a single class, SDLIAPSession
• Eliminates the use of NSThread from SDLIAPDataSession
• SDLIAPSession now uses a DispatchQueue to provide the required thread for EASession
• Uses composition instead of inheritance, SDLIAPControlSession and SDLIAPDataSession now use SDLIAPSession instead of being subclasses of it
• Provides a short simple code path for closing EASessions
• Eliminates over two hundred lines of code

Tasks Remaining:

• More unit tests

CLA

• I have signed the CLA

[NicoleYarroch]

I mostly made some style formatting suggestions. Namely, private methods in the implementation files are prefixed by "sdl_". I tried to find most of them but I may have missed a few.

I did experience a crash on disconnect that should be a pretty easy fix.

I haven't had the chance yet to thoroughly test secondary transports and switching between BT and USB transports but testing the multisession and control protocols worked well.

[kmicha19-ford]

Thanks Nicole, I have been without a work computer all week. Going into Dearborn today to get it fixed or replaced. I will look at what you have here in detail by Monday if not by EOD today. Mike

[kmicha19-ford]

Just commited changes based on PR comments. These include the following.
prefixing all private methods with 'sdl_'
removed blank space from beginning of method names
removed extraneous semicolons
moved one public method up that was in the marked as private section
Note, not sure about when to you want to use SDLLogD, SDLLogV or even SDLLogE

[NicoleYarroch]

I think a few things were missed from my last review. Can you tag me when you have a fix for the crash I noted in the last review? Thanks!

[codecov]

Codecov Report

Merging #1910 (2f8d655) into develop (67ca794) will increase coverage by 0.54%.
The diff coverage is 74.45%.

@@             Coverage Diff             @@
##           develop    #1910      +/-   ##
===========================================
+ Coverage    84.66%   85.20%   +0.54%     
===========================================
  Files          418      426       +8     
  Lines        20939    21376     +437     
===========================================
+ Hits         17728    18214     +486     
+ Misses        3211     3162      -49     

[kmicha19-ford]

I reviewed comments and made multiple updates for style requirements and also removed an used function. Hopefully I have everything this time.

[NicoleYarroch]

I found a few minor things to fix. A couple of comments from my previous reveiw were missed on the SDLIAPDataSession.m file.

[NicoleYarroch]

I found a few minor spacing issues - otherwise testing went well