fixing code analysis violation on string.format without culture
Merge pull request #398 from blairconrad/fix-format-analysis

fixing code analysis violation on string.format without culture
#30 - supporting raising nonstandard (delegate) events
#30 - removing Now, Go from event-raising API
#30 - post-fix tidying and test name cleanup
#395 - write specs to capture requirement
#395 - allowing Event.Raise to specify null senders