Low-level IR mutations for LLVM Bitcode

Hi folks,

Recently, I have extracted parts of a project into a separate library.
Since it is generic enough I thought that someone else may benefit from it as well.

Here is the link and brief description:

libirm is a library for low-level IR mutations of LLVM Bitcode.
The set of currently available mutations is driven by the needs of the Mull project,
so it is not exhaustive.