Couple of fixes:
- deepCopyIRConst failed to copy Ico_V256 constants
- deepCopyIRExpr did not copy Iex_Binder expressions
- handle_gets_Stmt should also handle an Ist_Put statement


git-svn-id: svn://svn.valgrind.org/vex/trunk@2953 8f6e269a-dfd6-0310-a8e1-e2731360e62c