Refactor compatibility extension methods

[Shane32]

Summary

Refactors the Stream.CopyTo method into a polyfill for .NET 3.5 only, and has IsNullOrWhiteSpace inline to the native implementation for available platforms. These methods are internal and the changes will not affect operation.

In addition, ReverseString and IsAllDigit methods were removed as they were not referenced within the codebase.

Test Plan

Existing tests cover both .NET 3.5 and other platforms, ensuring compatibility. The changed and removed methods are not publicly accessible.

[codebude]

Can we rewrite/use the IsNullOrWhiteSpace function as an extension method in the same manner as CopyTo? Currently at least in the PayloadGenerator.cs the calls aren't looking nice...

QRCoder/QRCoder/PayloadGenerator.cs

Line 2037 in 923dbe5

if (String40Methods.IsNullOrWhiteSpace(Secret))

if (Secret.IsNullOrWhiteSpace()) would look/feel smoother.

I'm sorry to mention such small things. But if we're going to tackle the points, I prefer to do it 100%. If I get too picky, let me know. Then I slow myself down a little. ;-)

[Shane32]

Certainly. I’ll double check and see. I know the native method is not an extension method. So we can’t just polyfill it like CopyTo. But we could alter the name slightly if nothing else. I’ll check.

[Shane32]

@codebude Looks like it works as anticipated !