refactor: build script
- reduce MSBuild console verbosity
- pipe detailed MSBuild log to file
- switch to cleaner 'artifacts' folder
- reduced MSpec console verbosity
- pipe detailed MSpec log to file
- suppress printing of release creation variables
- suppress NUnit logo
Merge pull request #396 from adamralph/refactor-build-script

refactor: build script
#30 - supporting raising nonstandard (delegate) events
#30 - removing Now, Go from event-raising API
#30 - post-fix tidying and test name cleanup