for InstructionData. Use generated `is_terminator()` for `Opcode`
instead. `is_terminator`, `can_trap` and `is_branch` functions are now
public.
fix syntax error
Give these crates each a more standard directory layout with sources in
a 'src' sub-sirectory and Cargo.toml in the top lib/foo directory.
Add license and description fields to each.
The build script for the cretonne crate now lives in
'lib/cretonne/build.rs' separating it from the normal library sources
under 'lib/cretonne/src'.
