Add options for timeout, schema restriction and dbo-prefixing

[rhumborl]

Added 3 new options:

1. timeout={secs} - specify the commandTimeout for queries, as this could exceed the default 30 secs on slow machines or large databases.
2. --noprefixdbo - not prefixing dbo files is only set for backwards compatibility. The consensus seems to be that they should be. By default they will now be prefixed. This option allows for older code bases to turn that off for compatibility.
3. schemas={a,b} - an optional comma-separated list of schemas names. Only objects within these will be scripted (plus global objects such as users and assemblies). This is useful for us as we have a few dev-only schemas in our db which we do not want to script to source control.

Additionally, I have swapped out the resharper test tools for the Nunit Test Adapter, as the generic test runner has been built into VS for quite a while now.

May fix #176