Update to Swift 4/Xcode 9.3#3

Open

skovatch wants to merge 6 commits intoBobElDevil:masterfrom

skovatch:master

Commits on May 8, 2018

Updated for Swift 4/Xcode 9.3
Scott Kovatch
committed
Reversed a substring.
Scott Kovatch
committed

Commits on Sep 20, 2018

Need @escaping to make the compiler happy again.
Scott Kovatch
committed

Commits on Sep 21, 2018

Made sure the type of UnsafeMutablePointer matched what we got from workingDirectoryTemplate.
Scott Kovatch
committed
Pull UnsafeMutablePointer outside of the usage; seems to behave better.
Scott Kovatch
committed
Trying again using withCString.
Scott Kovatch
committed