antocuni's older TODO:

* run coverage against the parser/astbuilder/astcompiler: it's probably full of
dead code because the grammar changed

* optimize W_UnicodeObject, right now it stores both an unicode and an utf8
version of the same string

* re-enable BUILD_LIST_FROM_ARG: see the comment in astcompiler/codegen.py in
ast.ListComp.build_container

* review use of std_decode_utf8, we probably do not want to be using it
