This pr introduces some cargo features. For `swc_common` and `swc_ecma_ast`, it introduces a feature flag `fold`.
`Fold` and `Visit` traits exist only if the feature is enabled.
For `swc_ecma_parser`, flag called `verify` is added. When disabled, we skip checking of validity of some expressions.
e.g. `{foo = bar}`
Verification is disabled by default it requires nightly compiler
- rename packages to be consistent
- `swc_macros` is removed. Now macros are imported with `extern crate macro_name` instead of `extern crate swc_macros`.
- manage atoms with words.txt file
common:
- rename `Folder` to `Fold`
- folder.then()
- impl Fold for Box<F>
- impl Fold<T> for &mut F where F: Fold<T>
transforms:
- make Simplifier private
- organize compat
codegen:
- use `Mark` to avoid deoptimization
swc:
- upgrade rayon and use global thread pool instead
