Update script to download Qt 4.8.6 and build it against openssl 1.0.1h

Also update how jom is found to adapt to how jom is exposed within new
version of chocolatey. This commit basically revert what was done
in commit 7387cf60b
Update cmake script version in powershell script
Update powershell script to ensure newer version of CMake script is downloaded
Update README.md to reference power shell script from 4.8.6 branch