* Continue cleanup of type printing code

* Continue cleanup of type printing code
* Print a newline after a malloc instruction
* Convert unprintable characters to x_ instead of _x so that we don't
  generate identifiers that start with underscores

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2577 91177308-0d34-0410-b5e6-96231b3b80d8