Reduce/remove use of ArchitectureSpecific

Architecture specific is generated by the ant build process. Its use allows, for example, the meaning of ArchitectureSpecific.VM_Assembler to either be ia32.VM_Assembler or ppc.VM_Assembler. Unfortunately by doing this we complicate things, most notably our ability to edit, with IDE features, PPC code when on IA32 or vice versa. We should phase out the use of ArchitectureSpecific and install proper class hierarchies for VM_Assembler and alike classes, this may mean optimization work in the compiler so that we avoid any performance hits (although these should be negligible).