833 Allow log level to be set in debug mode.
Always resolve null LogLevel to Info in ScriptServicesBuilderFactory.
Merge pull request #872 from jamiehumphries/833-debug-log-level

833 Allow log level to be set in debug mode.
Fix typo in test name.
Merge pull request #873 from jamiehumphries/dev

Fix typo in test name.
red: added RoslynScriptEngineTests.ShouldAllowUseOfScriptHostExtensionMethods to demonstrate that extension methods on script host do not work