Can now raise errors returning nil or NO
Consistent exception build settings

* C++ exceptions disabled via OTHER_CPLUSPLUSFLAGS in both iOS and OS X builds. See @82e4022.

* Objective-C exceptions disabled via GCC_ENABLE_OBJC_EXCEPTIONS in both iOS and OS X builds. This avoids the warning “argument unused during compilation: '-fno-objc-exceptions’”.
Use user-style #include in umbrella header
Improve doc comments
Improve and convert podspec to JSON

* Settings should be closer to original Xcode project file.
fix pod spec json include
Improve archive init API

* No more separate mutable archive subclass (ref #24).

* Initializers and factory methods may now return nil, along with error information.

* Initializers now take an options dictionary, which allows for expansion. For now, you can set ZZOpenOptionsEncodingKey for string encoding and ZZOpenOptionsCreateIfMissingKey to create the archive file if it is missing.

* Drop the public load: method, as initializers and updateEntries: do any necessary loading. It’s fairly cheap to create a new archive object to reload changed contents, and we no longer lazily load contents and entries.

* The redesign prevents creating erroneous objects e.g. file not found may be a legitimate problem, and prevents swallowing of read errors during lazy loading.

* Update podspec to version 8.0.
Refactor unit tests

* Move decrypt tests from unzip test case into its own test case. This avoids expensive unzip setup for decryption.

* Split zip tests into test cases for old and new archives. Setup is a lot cleaner and the classes are less monolithic and more encapsulated now.

* Test file and data channels.

* Remove zip data tests, since we now test data channels at a lower level.