fix issue86 - point to pytest-xdist plugin for looponfailing feature.

--HG--
branch : trunk

CHANGELOG

@@ -2,6 +2,8 @@ Changes between 1.2.1 and XXX
 =====================================
 
 - added links to the new capturelog and coverage plugins 
+- (issue87) fix unboundlocal error in assertionold code 
+- (issue86) improve documentation for looponfailing
 
 
 Changes between 1.2.1 and 1.2.0

doc/test/features.txt

@@ -176,7 +176,8 @@ advanced test selection and running modes
 
 .. _`selection by keyword`: 
 
-``py.test --looponfailing`` allows to run a test suite, 
+``py.test --looponfailing`` (implemented through the external
+`pytest-xdist`_ plugin) allows to run a test suite, 
 memorize all failures and then loop over the failing set
 of tests until they all pass.  It will re-start running
 the tests when it detects file changes in your project.