Portability part 1 - C99 printf

printf, sprintf, fprintf etc are now all C99 compliant. All except sprintf, which is now signaled as deprecated. This raises a few warnings about sprintf usage in the build. Some I fix with pull requests that will follow. Some others should be fixed by the respective authors.
Breaking the line mid-example is not good.  You also failed to close the double quote.
It wouldn't hurt to make the example a full call, too:
```
* When quoting strings, use single quotes, e.g.
   Log("Some stuff '%s' happened in '%s'.", stuff, context);
```