Fix super slow iOS Tests

[pietbrauer]

Updates dependencies to Nimble, Quick and SSZipArchive.

iOS Tests were running super slow (30 minutes total) this was because after every single test case the unzipped fixture repository would be deleted from disk and unzipped again from the 28MB big zip file. This was not an issue on Mac as unzip super fast (apparently) but SSZipArchive cannot quite keep up and so every single iOS test case would take 5-7 seconds to unzip + the time the test needs to run.

What I did is just unzip it once and store it in a directory called clean_repository, the directory is still removed after each test but instead of unzipping again I just copy the desired repository into its place not touching the clean_repository.

[pietbrauer]

ITS GREEEN!!!!

Due to the Quick Update I had to set the deployment target of the Tests to iOS 9.0 which does not affect the framework itself.

A nice side effect of the Quick Update is that test names are now actually readable. ✌️

[phatblat]

This is amazingly faster. Nice work!

Had one snag when running carthage bootstrap:

A shell task failed with exit code 74:
xcodebuild: error: Unable to read project 'SSZipArchive.xcodeproj' from folder '/Users/phatblat/dev/libgit2/objective-git/Carthage/Checkouts/ZipArchive'.
    Reason: Project /Users/phatblat/dev/libgit2/objective-git/Carthage/Checkouts/ZipArchive/SSZipArchive.xcodeproj cannot be opened because it is missing its project.pbxproj file.

It looks like checking out the v1.0.1 tag left an empty SSZipArchive.xcodeproj folder since there is no project.pbxproj in the tree at that tag.

This was due to having an older ZipArchive checkout which left behind the .xcodeproj folder and confused carthage and xcodebuild.

[phatblat]

One little nitpick, there's now a dead workspace reference to the SSZipArchive project.

[pietbrauer]

Yeah, SSZipArchive is a bit weird but we use the files directly.

[pietbrauer]

Will remove the file reference.

[phatblat]

Looks like v1.1 has framework targets now, but that can be updated in another PR.

[pietbrauer]

Updated SSZipArchive v1.1 and fixed the reference.

[pietbrauer]

Can't update to 1.1 because it has a lot of warnings. Staying on 1.0.1 but remove the reference to the project.

[phatblat]

Sounds good to me!