Changes --> CHANGES.md
Revert commits for installing camlp4 with ocamlfind
add the PaExc constructor

for `exception patt` in patterns.
bootstrap
support the `exception patt` syntax
bootstrap
add `type t +=` to the AST
Add `..` to types
support type extensions
bootstrap
support the `M()` syntax
bootstrap
fix the default value for PKGDIR