Refactoring the testpack tests
- AssetContainerBuilder classRefersTo() now uses varargs (as invoking it multiple times overwrites the file)
- Hardened bundledFilesEqual() to also compare the number of files (expected vs bundled)
- TestPackVerifier bundledFilesEqual() now outputs a nicer comparison string when there is a failure
Merge branch 'testPackImplementation' of https://github.com/BladeRunnerJS/brjs into testPackImplementation