* Add SLN file and make projects build in VS
- Added new ActionsRunner.sln file with all the CSPROJ's in it
- Added Directory.Build.props that gets auto-included in all CSPROJ files under it
- Made default runtime platforms for Windows and Linux (to be 64bit) so that you don't have to specify it in order to build
* Remove extra invalid parens
The build warnings were of these type (mostly reported by xUnit's Code Analyzers):
- Fixed wrong parameter order in xUnit assertions (can lead to poor error reporting in test failures)
- Unused code was removed
- Correct assertions were used (e.g. Assert.True/.Contains/.EndsWith)
- Public non-test methods on test classes were made private
