Apply R# clean-up for reliability (#877)

* Apply R# clean-up for reliability

- Migrate to NUnit4 Assert.That
- Update dependencise versions
- Fix LangVersion to 9.0 (until net core migration)
- Reformat code
- Apply 'var' style (easier for refactoring)
- Remove redundant parentheses
- Add braces on every condition blocks (1 line)
- Uses new null checking patterns
- Uses AutoProperties when possible
- Uses string scalar type instead of class
- Clean usings
- Add .orig files in git ignore
- Rename some properties to respect defined conventions and US format definition
	- ID -> Id
	- BPM -> Bpm
	- Finish -> End

* Update R# settings according to the clean-up made

Tests/Properties/AssemblyInfo.cs

@@ -1,5 +1,4 @@
 using System.Reflection;
-using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 // General Information about an assembly is controlled through the following 
@@ -30,4 +29,4 @@ using System.Runtime.InteropServices;
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
 [assembly: AssemblyVersion("1.0.0.0")]
-[assembly: AssemblyFileVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]