use variable tagging in harmony pluging (instead of magic renaming)
Parser no longer calls hooks.expression for x in `x = ...`, hooks.pattern is called instead
remove rootName argument from hooks.expressionMemberChain and hooks.callMemberChain
add Compiler.intermediateFileSystem
avoid using `path` and `fs` module when possible
move `join`, `mkdirp` and `dirname` into utils
join and dirname is optional in FileSystem interface
remove mkdirp from Filesystem interface