Create quads hierarchy

* Move nquads into quad.
* Create cquads simplified parser in quad.
* Move Triple (renamed Quad) to quad.

Also made sure mongo actually implements BulkLoader.

quad/cquads/actions.rl

@@ -0,0 +1,95 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+%%{
+	machine quads;
+
+	action Escape {
+		isEscaped = true
+	}
+
+	action Quote {
+		isQuoted = true
+	}
+
+	action StartSubject {
+		subject = p
+	}
+
+	action StartPredicate {
+		predicate = p
+	}
+
+	action StartObject {
+		object = p
+	}
+
+	action StartLabel {
+		label = p
+	}
+
+	action SetSubject {
+		if subject < 0 {
+			panic("unexpected parser state: subject start not set")
+		}
+		q.Subject = unEscape(data[subject:p], isQuoted, isEscaped)
+		isEscaped = false
+		isQuoted = false
+	}
+
+	action SetPredicate {
+		if predicate < 0 {
+			panic("unexpected parser state: predicate start not set")
+		}
+		q.Predicate = unEscape(data[predicate:p], isQuoted, isEscaped)
+		isEscaped = false
+		isQuoted = false
+	}
+
+	action SetObject {
+		if object < 0 {
+			panic("unexpected parser state: object start not set")
+		}
+		q.Object = unEscape(data[object:p], isQuoted, isEscaped)
+		isEscaped = false
+		isQuoted = false
+	}
+
+	action SetLabel {
+		if label < 0 {
+			panic("unexpected parser state: label start not set")
+		}
+		q.Provenance = unEscape(data[label:p], isQuoted, isEscaped)
+		isEscaped = false
+		isQuoted = false
+	}
+
+	action Return {
+		return q, nil
+	}
+
+	action Comment {
+	}
+
+	action Error {
+		if p < len(data) {
+			if r := data[p]; r < unicode.MaxASCII {
+				return q, fmt.Errorf("%v: unexpected rune %q at %d", quad.ErrInvalid, data[p], p)
+			} else {
+				return q, fmt.Errorf("%v: unexpected rune %q (\\u%04x) at %d", quad.ErrInvalid, data[p], data[p], p)
+			}
+		}
+		return q, quad.ErrIncomplete
+	}
+}%%