Update to _MEM examples in wiki

[SMcNeill]

I was looking at our page on _MEM in the wiki this evening, and none of our examples would work 100% as written on it.  Our first example was using a LONG for reference as an _OFFSET, which isn't allowed.  The second example just didn't have much of an explanation to it and was confusing as written without some comments to showcase what it was trying to accomplish.  The third example fell victim to the the changes to recursive functionality, back around version 2.something, so it wouldn't work at all either.

https://qb64phoenix.com/qb64wiki/index.php/MEM

I've updated those examples.  Prettified them. (Thanks to Rho's "EXPORT AS WIKI PAGE" addition to the IDE -- that's an EXCELLENT addition/tool for us!!)  Take a look at them and let me know if they work as advertised now, and if they pretty much explain what each of them is trying to do and showcase for us.  

I'll make edits, updates, additions, whatever, as you guys suggest on them. 

[mnrvovrfc]

Many months ago I was trying to get through that using `ConvertOffset` name directly like a variable inside that function didn't work for me and otherwise was going to cause trouble. It was better to write the 64-bit part most similar to the 32-bit one. This is one of the most useful functions listed in the Wiki. Good work.

[James D Jarvis]

Thanks. I thought I was just being a tad dense when working with _mem.