Add the ability to create keys from certificate private keys
This PR allows your tool to create ppk files from a given private key. I also rounded out the ability to read, write, and verify all the putty version formats (SSH1 1.1, and the more current 1,2, and 3).
Thanks for the PR. It's quite a big change and I need a bigger free time slot to review it.
@kayrus I am sorry for the go test not passing on the PR on the first submission. I thought I had pushed my latest change on disk and blindly did the PR before doing the commit and push. I appreciate your patience. The test should be good now!
@kayrus: Just a heads up here, I finished implementing the SSH1 read and writing routines, so this library can thoroughly read and write every possible putty key format!
All the best!
@pschou I apologies for the delay. Could you please rebase your branch to resolve the conflicts? I'll try to review this PR ASAP.