Make barrierQueue serial

[MontakOleg]

Resolves #26

[vadymmarkov]

Awesome, thanks @MontakOleg 👍

[MontakOleg]

Hm..

*** Skipped downloading Quick.framework binary due to the error:

	"Maximum number of login attempts exceeded. Please try again later."

*** Checking out Quick at "v1.1.0"

It looks like binary not available, so Carthage builds dependencies from sources using following command:

"travis_wait 35 carthage bootstrap --platform iOS,Mac"

Then tests run on tvOS platform

"xcodebuild test -project When.xcodeproj -scheme \"When-tvOS\" -destination 'platform=tvOS Simulator,name=Apple TV 1080p,OS=10.0' | xcpretty && exit ${PIPESTATUS[0]}"

And finally Quick not found for tvOS:

No such module 'Quick'

So we need add tvOS platform to Carthage bootstrap command like this:

"travis_wait 35 carthage bootstrap --platform iOS,Mac,tvOS"

[vadymmarkov]

Let's see how it goes.

[vadymmarkov]

@MontakOleg v3.0.1 is released 😉