fix casting between UnsafeMutablePointer<CChar> and UnsafePointer<CCh…

…ar>!

make posix spawn file actions in linux and macos

Merge pull request #3 from bow-swift/environment

Set environment in task executors

fix clean up memory in log task executor

Delete Readme.md

remove outdated README

SPM compatibility

Merge pull request nsomar#25 from oarrabi/swift3

Moving to swift3