GPU: Improve frame synchronization, increases compatibility with both homebrew and retail applications.

This cleans up the mess that address reading/writing had become and makes the code a *lot* more sensible.
This adds a physical<->virtual address converter to mem_map.h. For further accuracy, we will want to properly extend this to support a wider range of address regions. For now, this makes simply homebrew applications work in a good manner though.

While it was some nice and fancy template usage, it ultimately had many practical issues regarding length of involved expressions under regular usage as well as common code completion tools not being able to handle the structures.
Instead, we now use a more conventional approach which is a lot more clean to use.

GPU: Updated g_last_ticks variable to be more descriptive (represents CPU tick count of last vertical line).

- Various other cleanups.

Core: Added a comment to explain the logic for the RunLoop iterations.

Also makes the illogical component order more obvious.

- added hooks to catch LCD IO read/writes

changed hw_lcd to use ARM core correct tick counter instead of [what was actually] just an instruction count. this seems to fix timing issues with the 3DS_Homebrew_Pong3Dv2 demo.