document true_value and false_value flags on gcc.Edge
add a new internal API for describing the CPython API

Introduce a new API within libcpychecker/refcounts.py in the hope of
decoupling the description of the CPython API from the mechanics of the
checker (FunctionCall and Outcome objects).

Port various functions to it
further work on new internal API
introduce FunctionCall.crashes_on_null_arg()

Introduce FunctionCall.crashes_on_null_arg() and use it in a few places
within the API description, rather than working directly on states, to try
to further decouple the API description from the analysis implementation.

Introduce Outcome.is_possible, so that outcomes that are impossible for
certain arguments can be marked

Rework the varous Outcome.returns methods to capture the provided return value
port PyErr_SetFromErrno to new API
port PyErr_PrintEx to new API

Also update description of outcome for FunctionCall.always() to
add "calling"
port Py_FatalError to new API
fix stray quotes
port more impl_ code to new API
document gcc.SsaName
ensure that there is a unique gcc.Edge wrapper for each underlying gcc edge
fixes for compiling the plugin with a C++ compiler
further C++ compilation fixes
more C++ compilation fixes (casts and signedness)
docs/success.rst: add another bug found in itself
autodetect whether the plugin needs to be built with C++

Recent builds of gcc 4.7 are built with C++, rather than C, and so the
internal symbols are name-mangled.

Try to determine whether or not the GCC we're building against was built with
C++; if so, supply "-x c++" during the build of the plugin.

Generate a new autogenerated-EXTRA_CFLAGS.txt containing additional flags
needed during compilation, so that this can hold "-x c++" if needed.
add Makefile rule to note that autogenerated-EXTRA_CFLAGS.txt is a byproduct of making autogenerated-config.h
bump to 0.11
fix "make demo"

Update "make demo" to use PYTHON_INCLUDES rather than PYTHON_CFLAGS (which
went away in 99da8c8d990d254b328f4b65d4d58f527c8acb74).

Also, add "-c" since we only care about *compiling* the code (to see the
new warnings)
add example of refcounting bugs to "make demo"