add test to check pkg-config and rtm-config returns same and valid value

This is discussed in #1, #41, and we still have to think about prefix and exec_prefix problem.

currently it may fails due to 
+        self.check_if_file_exists("libdir",             "libRTC.a")    # currently pkg-config returns lib/ and rtm-config retuns .../lib/openrtm-1.1
+        self.check_if_file_exists("includedir",         "openrtm-1.1") # rtm-config does not have --includedir