rewrote mrb_any_to_s

use %p instead of %lx to prevent truncation and for consistency
Merge pull request #823 from cremno/mrb_any_to_s-rewrite

mrb_any_to_s rewrite
Add semi-colon after the statement.
Merge pull request #824 from monaka/pr-add-semicolon

Add semi-colon after the statement.
changing Make_Data_Struct API; you need to modify your code that uses Make_Data_Struct; close #821