SkyEye dyncom interpreter

Integrates the SkyEye "dyncom" interpreter (from sourceforge.net/p/skyeye/code/ci/master/tree/arch/arm/dyncom/). This is a faster, more modern ARM11 interpreter core, used by the SkyEye project as a "hybrid" mode with their dynamic recompiler. I'd like to get some feedback/testing done with this PR before being merged. By default, the new interpreter is not enabled, but can be with the following patch:

https://gist.github.com/bunnei/c1b14a760fb9190e97bd

Furthermore, if interested in seeing the best performance with yeti3DS (and other homebrew), try the following speedhack (I've yet to find a correct workaround, hence why I won't be committing this):

https://gist.github.com/bunnei/702a6b6449d8f7b6216d


Gosh, I always forget whether we agreed on using `s_` prefixes or on the opposite. Judging from my pica code, it seems we agreed on not using them.