get rid of the stop_list type

unnecessary since doing a fold of compile_dec1 anyway?
rename the eval compile_decs to fold_compile_top

because there's already a different compile_decs in compilerTheory
move bootstrapProofs into compiler/proofs, and move fold_compile_top into it

the theorem required for bootstrapping shouldn't have to depend on the
bootstrapping evaluation theory (it's slightly more general).
not sure if compile_repl_step still builds - will try asap
rework compile_repl_step to use compile_decs from the compiler

no separate fold_compile_top function. this means the bootstrap will
happen as if inside a module, but that shouldn't matter. although the
correctness theorem might require something to set up and destroy the
exception handler on the outside...