added thread.h include (necessary since 227c847135c5d85cf0e9fe5770f5c47a0e5cba3b)
handle sigterm, inform about exit

resolves #445
Merge pull request #447 from OlegHahm/thread_include

added thread.h include (necessary since 227c847135c5d85cf0e9fe5770f5c47a0e5cba3b).
added ENABLE_DEBUG macro
added missing thread include
Merge pull request #448 from LudwigOrtmann/pyterm

handle sigterm, inform about exit
Merge pull request #449 from mehlis/fix-yield

Fix yield (missing part)