Xcode10, Swift 4.2 compatibility

Whitespaces handling for fileOutputHandler.

Functionality to zip data from memory

The purpose of this change is to add functionality for zipping files
from memory rather than files. This removes the necessity to write a
generated file to disk before being able to archive, thus saving lots of
disk i/o.

The struct `ArchiveFile` represents the same data that is loaded from a
file.

The new method `zipData` allows an array of `ArchiveFiles` to be passed
rather than file URLs and are zipped accordingly. Other functionality
remains identical.

Update Zip.podspec with Swift version

Update swift version to 4.1 for Xcode 9.3.

Aligned Minizip module name with the official repository

Fixed issue with address sanitizer

Documents directory doesn't exist for tvOS device

After upgrading to Xcode 9.3, I get the following error:
dyld: Library not loaded: @rpath/libswiftCore.dylib
  Referenced from: /Users/chris/Library/Developer/CoreSimulator/Devices/.../data/Containers/Bundle/Application/.../RE-vibe.app/Frameworks/Zip.framework/Zip
  Reason: image not found

I have tried several different approaches, but none have fixed the issue. I suspect the the swift version for this package needs to be upgraded to match Xcode 9.3's version.

Documents directory doesn't exist for tvOS device.

String warnings

Added includeRootDirectory logic.

Fix Swift 4 string compiler deprecation warning.

Enables zipping of directory contents, i.e. not including root directory in zip.
Equivalent to user cd'ing into directory and zipping.

Functionality left as default, but logic is now there to enable above by either toggling boolean, or modifying other functions to enable toggling per call.

Also, expandDirectoryFilePath function comment changed. It's not a recursive function :)

Add fwrite() and uncompressed_size validation

support swift 4.0 

unzip file handler support

https://github.com/marmelroy/Zip/issues/78