- More code cleanup and codestyle updates

- Fixed some possible nullref exceptions
- Methods signatures now have up to 3 parameters before breakaing down each parameter in a separate line
- Method invocations have the same rule, except the first parameter will be in the same line as the invocation to prevent some ugliness when passing lambas as arguments
- Applied many more codestyles
- Extensions folder fully reformatted

src/NadekoBot/Common/Attributes/NadekoCommand.cs

@@ -7,9 +7,7 @@ public sealed class NadekoCommandAttribute : CommandAttribute
 {
     public NadekoCommandAttribute([CallerMemberName] string memberName="") 
         : base(CommandNameLoadHelper.GetCommandNameFor(memberName))
-    {
-        this.MethodName = memberName.ToLowerInvariant();
-    }
+        => this.MethodName = memberName.ToLowerInvariant();
 
     public string MethodName { get; }
 }