Add documentation

slapos/recipe/README.seleniumrunner.txt

 seleniumrunner
 ==========
-Allows to run selenium tests through browser and xvfb.
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+Allows to run selenium tests through browser and xvfb. Posts the results on
+Nexedi ERP5.
+
+Parameters
+=====
+  * project : name of the project inside of ERP5 test result instance
+  * user : username to use in ERP5 instance to test
+  * password : password to use in ERP5 instance to test
+  * suite_name : name of test suite to launch 
+  * url : url to portal_test of ERP5 isntance to test
+  * test_report_instance_url : url of test_result_module to put results
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