Re-Design for ObjectFileXCOFF - 64/32 bit (#72)

This is the New design for the ObjectFileXCOFF using LLVM interfaces.

The intent for which I had to implement this is that
we don't need to create new structures and can use LLVM interfaces instead, which makes the code cleaner,
safer and more structured.
And community was not accepting the older design.

As a plus, I have also made sure that it is able to handle 32 bit binaries too along with 64 bit

I have discarded the older design and only kept whats necessary, without changing any existing behaviour.

Most of this code has already been reviewed and merged in the community,
so I am pulling it together again here in our fork branch.

Author: DhruvSrivastavaX