NRE Support

@Nils-TUD, I reordered your commits and squashed everything NRE related into one commit. Regarding compiler.h: If the defintions clash with what's already provided and those defintions have incompatible meanings, things will be broken. I tend to rename the seoul macros to SEOUL_* or VMM_* or something and move compiler.h back to the generic part. Is there any reason not to do this? I don't get the flexibility argument.