Update help file.

cli-options.txt

@@ -73,9 +73,10 @@ Other Options:
   -f, --failfast        Stop execution at the first test that fails, errors,
                         or unexpectedly succeeds.
   -c FILE, --config FILE
-                        Use this config file instead of the one pointed to by
-                        environment variable GREEN_CONFIG or the default
-                        ~/.green
+                        Use this config file to override any values from the
+                        config file specified by environment variable
+                        GREEN_CONFIG, ~/.green, and .green in the current
+                        working directory.
   -p PATTERN, --file-pattern PATTERN
                         Pattern to match test files. Default is test*.py
   -n PATTERN, --test-pattern PATTERN
@@ -124,12 +125,21 @@ ENABLING SHELL COMPLETION
 
 CONFIG FILES
 
-  Green will look for and process three config files if found:
+  Configuration settings are resolved in this order, with settings found later in
+  the resolution chain overwriting earlier settings (last setting wins).
+
   1) $HOME/.green
-  2) $GREEN_CONFIG
-  3) A file specified with "--config FILE"
+  2) A config file specified by the environment variable $GREEN_CONFIG
+  3) .green in the local directory (the current working directory of the test run)
+  4) A config file specified by the command-line argument "--config FILE"
+  5) Command-line arguments.
+
+  Any arguments specified in more than one place will be overwritten by the value
+  of the LAST place the setting is seen.  So, for example, if a setting is turned
+  on in ~/.green and turned off by a command-line argument, then the setting will
+  be turned off.
 
-  Config file format is simply "option = value" on separate lines.  "option" is
+  Config file format syntax is "option = value" on separate lines.  "option" is
   the same as the long options above, just without the "--".
 
   Most values should be "True" or "False".  Accumulated values (verbose, debug)