streamline pytester API majorly:

- integrate conftest into pytester plugin
- introduce runpytest() to either call runpytest_inline (default) or
  runpytest_subprocess (python -m pytest)
- move testdir.inline_runsource1 to pdb tests
- strike some unneccessary methods.
- a new section "writing plugins" and some better pytester docs

--HG--
branch : testrefactor

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 distshare={homedir}/.tox/distshare
-envlist=flakes,py26,py27,py34,pypy,py27-pexpect,py33-pexpect,py27-nobyte,py33,py27-xdist,py33-xdist,py27-trial,py33-trial,doctesting,py27-cxfreeze
+envlist=flakes,py26,py27,py34,pypy,py27-pexpect,py33-pexpect,py27-nobyte,py33,py27-xdist,py33-xdist,{py27,py33}-trial,py27-subprocess,doctesting,py27-cxfreeze
 
 [testenv]
 changedir=testing
@@ -9,6 +9,15 @@ deps=
     nose
     mock
 
+[testenv:py27-subprocess]
+changedir=.
+basepython=python2.7
+deps=pytest-xdist
+    mock
+    nose
+commands=
+  py.test -n3 -rfsxX --runpytest=subprocess {posargs:testing}
+
 [testenv:genscript]
 changedir=.
 commands= py.test --genscript=pytest1
@@ -136,7 +145,7 @@ commands=
 minversion=2.0
 plugins=pytester
 #--pyargs --doctest-modules --ignore=.tox
-addopts= -rxsX 
+addopts= -rxsX -p pytester
 rsyncdirs=tox.ini pytest.py _pytest testing
 python_files=test_*.py *_test.py testing/*/*.py
 python_classes=Test Acceptance