Fixes issues 3, 4 and 7

[bugal]

Fixes some issues, so it works on clustered scenarios, and also adds some informational outputs when it can't find SQL Server instances or gets connection errors.
Tested on SQL Server 2008R2, SQL Server 2012 and SQL Server 2012 Cluster.

[aph3rson]

@bugal thanks for the PR - just a couple quick notes I was going to mention:

• It looks like your commits don't have an email set, so you wouldn't get credit for commits to the repo. If you'd like to go back and reauthor your commits (this guide should be helpful), it should resolve that.
• Your commit titles have #iss3/etc. in them - this won't link to the specific issue you're referring to. Instead, you should add something along the lines of Fixes NetSPI/Powershell-Modules#3 or Works on NetSPI/Powershell-Modules#3, which Github will autolink to that issue, and you'd see a handy note there accordingly.

Note that both of these changes are considered "rewriting history" on Github - therefore, a force push is required, which generally isn't kosher on PRs. However, if you'd like to do a force-push on your branch with these changes, I can get this assigned for review.

[bugal]

Thanks for the reply, @aph3rson, I'm still getting used to github.
I did as you oriented, and it appears to be ok now.

[aph3rson]

I've taken a precursory look at the code, and it looks good. I'm asking the reporters of #4 to try the changes out on their side, as I don't have a clustered environment handy.