Fix `mvn -Plight-test install` on Ubuntu 13.04 with OpenJDK

* FilePathTest#testCopyToWithPermission would fail because it would fall back to using Ant chmod as the `GNUCLibrary.LIBC` could not be linked. Migrating calls form `GNUCLibrary.LIBC` to jnr-posix resolved many of the linking issues.

* FilePathTest#testErrorMessageInRemoteCopyRecursive was exceptionally slow as it would create thousands of files to test an error that could be demonstrated with one.

Potential enhancements:
* Currently there are usages of both `GNUCLibrary.LIBC` and jnr-posix it would be awesome to migrate to just jnr-posix.
* Prior to many of the chmod calls, a check is made to see if the current platform is not windows. We should test to see what jnr-posix does with those calls to see if we can remove all the platform checks.