drc: extend drc-rules file format with length and skew tokens

common/drc_rules.keywords

@@ -10,6 +10,7 @@ graphic
 hole
 inner
 layer
+length
 max
 micro_via
 min
@@ -19,7 +20,6 @@ outer
 pad
 pth
 rule
-selector
 text
 track
 track_width
@@ -31,6 +31,5 @@ hole_clearance
 courtyard_clearance
 silk_to_pad
 silk_to_silk
-match_lengths
-match_skew
+skew
 diff_pair

pcbnew/drc/drc_rule_parser.cpp

@@ -282,7 +282,10 @@ void DRC_RULES_PARSER::parseConstraint( DRC_RULE* aRule )
     case T_track_width:         constraint.m_Type = DRC_CONSTRAINT_TYPE_TRACK_WIDTH;         break;
     case T_annular_width:       constraint.m_Type = DRC_CONSTRAINT_TYPE_ANNULAR_WIDTH;       break;
     case T_disallow:            constraint.m_Type = DRC_CONSTRAINT_TYPE_DISALLOW;            break;
+    case T_length:              constraint.m_Type = DRC_CONSTRAINT_TYPE_LENGTH;              break;
+    case T_skew:                constraint.m_Type = DRC_CONSTRAINT_TYPE_SKEW;                break;
     default:
+    // fixme: message
         msg.Printf( _( "Unrecognized item '%s'.| Expected %s." ),
                     FromUTF8(),
                     "'clearance', 'track_width', 'annular_width', 'hole', 'disallow'."