Add modules.grains.list and change the default outputter

Just make the grains module a bit friendlier. Also, since  the
default output of: salt-call -g is yaml, do the same in output
of: salt-call grains.items

Indent all json printed out from salt-call by 2 characters

salt/cli/caller.py

@@ -65,7 +65,8 @@ class Caller(object):
         grains = salt.loader.grains(self.opts)
         printout = self._get_outputter(out='yaml')
         # If --json-out is specified, pretty print it
-        printout.indent = 2
+        if 'json_out' in self.opts and self.opts['json_out']:
+            printout.indent = 2
         printout(grains)
 
     def _get_outputter(self, out=None):
@@ -99,5 +100,7 @@ class Caller(object):
                 printout = self._get_outputter(ret['out'])
             else:
                 printout = self._get_outputter()
+            if 'json_out' in self.opts and self.opts['json_out']:
+                printout.indent = 2
 
             printout({'local': ret['return']}, color=self.opts['color'])

salt/modules/grains.py

@@ -5,6 +5,12 @@ Control aspects of the grains data
 # Seed the grains dict so cython will build
 __grains__ = {}
 
+# Change the default outputter to make it more readable
+__outputter__ = {
+    'item' : 'txt',
+    'items': 'yaml',
+}
+
 
 def items():
     '''
@@ -28,3 +34,16 @@ def item(key):
     if key in __grains__:
         return __grains__[key]
     return ''
+
+def list():
+    '''
+    Return a list of all available grains
+
+    CLI Example::
+
+        salt '*' grains.list
+    '''
+    return sorted(__grains__.keys())
+
+# Keep the wise 'nix beards happy
+ls = list