Update OpenSSL to 1.0.1j (spec version 1.0.110)

Added a new spec version for 1.0.1j and also split out the build script into a separate `prepare_command.sh` file for easier testing and a more readable spec.

Note that I couldn't get this or any previous version of the spec to lint cleanly. It looks like a CocoaPods limitation on specs with tarball style `source` entries. However, I found a workaround:

```bash
$ wget -O file.tgz https://www.openssl.org/source/openssl-1.0.1j.tar.gz
$ pod lib lint

 -> OpenSSL (1.0.110)

OpenSSL passed validation.
```

With the `file.tgz` file in place, this spec lints clean on 0.33.1 and 0.34.4.