Better handling of empty type/name attributes in YAML config.

From #38

kibot/config_reader.py

@@ -51,11 +51,15 @@ class CfgYamlReader(object):
     def _parse_output(self, o_tree):
         try:
             name = o_tree['name']
+            if not name:
+                raise KeyError
         except KeyError:
             config_error("Output needs a name in: "+str(o_tree))
 
         try:
             otype = o_tree['type']
+            if not otype:
+                raise KeyError
         except KeyError:
             config_error("Output `"+name+"` needs a type")
 
@@ -63,6 +67,8 @@ class CfgYamlReader(object):
             comment = o_tree['comment']
         except KeyError:
             comment = ''
+        if comment is None:
+            comment = ''
 
         name_type = "`"+name+"` ("+otype+")"
 
@@ -99,6 +105,8 @@ class CfgYamlReader(object):
             config_error(kind_f+" needs a name in: "+str(o_tree))
         try:
             otype = o_tree['type']
+            if not otype:
+                raise KeyError
         except KeyError:
             config_error(kind_f+" `"+name+"` needs a type")
         # Is a valid type?

tests/yaml_samples/error_no_type.kibot.yaml

@@ -5,6 +5,7 @@ outputs:
   - name: PDF
     comment: "PDF files"
     dir: PDF
+    type:
     options:
       exclude_edge_layer: false
       exclude_pads_from_silkscreen: false

tests/yaml_samples/error_var_wrong_type.kibot.yaml

@@ -3,4 +3,4 @@ kibot:
 
 variants:
   - name: ok
-    type: ''
+    type: 'foobar'