move profiling utility code into external .c file
minor code simplification
whitespace
implement experimental support for line tracing
fix tracing check outside of functions
fix build
merge
prepare release of 0.19 beta 1
remove unused left-over code
enable Py_TPFLAGS_HAVE_VERSION_TAG on extension types by default (also in Py2) and provide 'type_version_tag' option to disable it
test 'type_version_tag' directive and fix it in Py2

--HG--
rename : tests/compile/ext_attribute_cache.pyx => tests/run/ext_attribute_cache.pyx