Minor code restructure to improve support for testing.

Moved allocation and preparation of hook object into LhAllocateHook - this function allows testing the creation of a hook without affecting the original entry point.

git-svn-id: https://easyhook.svn.codeplex.com/svn@74661 142e9c35-602f-4880-9f37-ec48a24daa6a
Closes #25592 and Closes #25487

* Added support for negative RIP addresses
* Fixed possible endless loop for a16 flag (still incomplete implementation but no longer hangs)
* Fixed RIP address relocation for instances where the address portion is not the last part of the instruction
* Added FORCE(...) around LhRelocateRIPRelativeInstruction

git-svn-id: https://easyhook.svn.codeplex.com/svn@74662 142e9c35-602f-4880-9f37-ec48a24daa6a