reimplement PEP 3155 __qualname__ calculation in a dedicated transform to base it on the node structure instead of the scopes (which fails for class scopes)

properly handle expressions at the beginning of func/class/etc. blocks that start with a string literal but are not docstrings

--HG--
extra : transplant_source : %94%87%D7e%B9%82%EF%926%26o%C0%8E%0DcY%C3%E3n%DB

--HG--
extra : rebase_source : 562b717b9c1e078b3f83e3febc8addc1a29d85fe

work around inability to detect existing Python globals (e.g. from imports) when cpdef-ing global functions

refactor analyse_types() and friends to work more like a transform by returning the node or a replacement

rewrite except-as semantics using try-finally - seems to be the easiest way to get flow control analysis working for all cases

make AnalyseDeclarationsTransform inherit from EnvTransform to fix inconsistencies in scope tracking

--HG--
extra : transplant_source : %FE%F3%DD2%1F-DN%11%05%F1%F5%1C%B3%B2C%90a%0C%10

that does not end by a new line

This is necessary to use some C++ APIs, and ugly if not impossible
to work around using cname specifiers and external files.