Now broken into two modules, one for loading RDI DLLs off disk and
finding the loader function offset, and another for doing the process
specific stuff of loading into the target.
MSF was starting to see more modules using RDI to load binaries into
remote processes, so it made sense to create a mixin which contained
the functionality that was being used in various locations.
This commit contains the new mixin, and adjustments to all the existing
exploits and modules which use RDI.