Import libgum for the time being, possibly to be used prebuilt later.
Add project files for Gum, reorganize and fix some warnings.
Update gum project file filters.
Interceptor support for relocating position-dependent prologue instructions.

Only 32 bit for now, 64 bit to follow later once Relocator supports it.
Add Gum.Stalker to project files.
Gum.Stalker support for indirect call to address in register.
Remove CRs that were accidentally added.
Gum Stalker test code cleanup and new naming scheme.
Stalker support for indirect call with register and immediate.
Remove CRs that snuck in.
Refactor most of the Stalker call tests.
Move Stalker fixture into separate file and update copyright headers.
Stalker support for indirect call through esp with immediate.
Refactor branch target handling and support jumps with immediate and scaled register.
Bump static limits and conditionalize debug.
Remove unused argument.
Add some hackish debug code and tweak branch handling.
Remove last_jump_site debug and clean up a bit.
Fix pool configuration and add guard assert to prevent future mistakes.
Disable debug code (to be removed later).