Kellyroach/fix warnings

[kellyroach]

This pull request fixes assorted Xcode 9.4.1 compiler warnings in TwitterCore, TwitterKit, and DemoApp of the twitter-kit-ios SDK . We've gone to some lengths to get Analyze / "iPhone X" to be equal to "No issues" on all 3 of these projects and also check unit tests are still passing and DemoApp functions plausibly. We would encourage Twitter software engineers, who are the experts, to review the pull request carefully due to the size and complexity.

[CLAassistant]

All committers have signed the CLA.

[kellyroach]

TEST: TwitterCore

Test Suite 'TwitterCoreTests.xctest' passed at 2018-07-14 16:09:34.429.
	 Executed 350 tests, with 0 failures (0 unexpected) in 0.979 (1.160) seconds
Test Suite 'All tests' passed at 2018-07-14 16:09:34.431.
	 Executed 350 tests, with 0 failures (0 unexpected) in 0.979 (1.162) seconds

[kellyroach]

TEST: TwitterKit

Test Suite 'TwitterKitTests.xctest' passed at 2018-07-14 16:08:11.718.
	 Executed 821 tests, with 0 failures (0 unexpected) in 7.398 (8.064) seconds
Test Suite 'All tests' passed at 2018-07-14 16:08:11.722.
	 Executed 821 tests, with 0 failures (0 unexpected) in 7.398 (8.069) seconds

[kellyroach]

TEST: DemoApp
A MIA Config.xcconfig is resolved for us by copying Config.xcconfig.example to Config.xcconfig .
The DemoApp built, ran, and exercised on "iPhone X" simulator. We explored various of the view controllers. There is plausiblity in what we saw. We leave it to the judgement of Twitter software
engineers whether or not everything is actually working here.

Our feeling is that there probably should not a lot of difference, if any, due to the nature of our
P.R., which is to fix static code lint issues detected by Xcode Analyze on the three projects TwitterCore, TwitterKit, and DemoApp of the twitter-kit-ios SDK .

[gintechsystems]

@kellyroach I was trying to pull in your git version of this in cocoapods but it is not working, any idea why? I receive "[!] Unable to find a specification for 'TwitterKit'.".

For now, I just downloaded the zip and added the framework locally.

[kellyroach]

RE: CocoaPods . I think "I just downloaded the zip and added the framework locally"
is probably best for now. My P.R. really can't and so doesn't modify Twitter's *.podspec
contents nor their locations in Twitter's repo.

[gintechsystems]

I understand, thank you for getting back to me.