* re-sort option groups, disable some options for now
* add docstrings to execnet gatewaymanage
* streamline tests a bit
* unify debugging and tracing
--HG--
branch : trunk
correct implementation of the xfail plugin: previously
--pdb and -x would incorrrectly terminate if seeing
a marked-to-fail test.
--HG--
branch : trunk
this merge contains:
* a new plugin architecture
* a pluginized pytest core
* many pytest related refactorings
* refactorings/streamlining of pytest's own tests
--HG--
branch : trunk
hpk