rename pb_annotation and move it to openfpga namespace

libopenfpga/libarchopenfpga/src/pb_type_annotation.h

@@ -1,5 +1,5 @@
-#ifndef PB_PHYSICAL_ANNOTATION_H
-#ifndef PB_PHYSICAL_ANNOTATION_H
+#ifndef PB_TYPE_ANNOTATION_H
+#ifndef PB_TYPE_ANNOTATION_H
 
 /********************************************************************
  * Include header files required by the data structure definition
@@ -7,6 +7,9 @@
 #include <vector>
 #include <map>
 
+/* namespace openfpga begins */
+namespace openfpga {
+
 /********************************************************************
  * This file include the declaration of data structures
  * to store physical pb_type annotation, including
@@ -48,5 +51,7 @@ class PhysicalPbAnnotation {
     std::vector<std:map<std::string, std::string>> interconnect_circuit_model_names_;
 };
 
+} /* namespace openfpga ends */
+
 #endif