Support added for multiple readers

[bergeraaron]

Added support to look for readers that are connected and if there are multiple allow the user to select which one to use.

[ikspress]

E:/mfoc/src/mfoc.c:793:38: warning: if statement has empty body
      [-Wempty-body]
  793 |     if(scanf("%d",&userselected) > 0);
      |                                      ^
E:/mfoc/src/mfoc.c:793:38: note: put the semicolon on a separate line
      to silence this warning
1 warning generated.

Please replace int userselected with size_t userselected and remove the empty body.