Fix #462 - Nicer error when a extensionless script name is passed
added missing null checks
added CA1062 'Validate arguments of public methods' to ruleset
added test ruleset with CA1062 omitted
Merge pull request #480 from adamralph/null-checks

Added missing null checks
Merge pull request #479 from dpen2000/fix-462

Fix #462 - Nicer error when a extensionless script name is passed
Merge branch 'dev' of https://github.com/scriptcs/scriptcs into invalid-load-notice