Add implementation of #3, "Operation Naming System"

Adds:

• GraphComponent interface that interfaces necessary functions for a graph component
• Abstract class AbstractGraphComponent that implements name
• Change so that SFG uses the GraphComponent interface instead of handling Operation and Signal separately
• Add a way for SFG to access graph components by name

Adds the implementation needed for #3 (closed) but not the testing yet.

b_asic/__init__.py

@@ -2,9 +2,11 @@
 Better ASIC Toolbox.
 TODO: More info.
 """
-from _b_asic import *
-from b_asic.basic_operation import *
+from b_asic.abstract_graph_component import *
+from b_asic.abstract_operation import *
 from b_asic.core_operations import *
+from b_asic.graph_component import *
+from b_asic.graph_id import *
 from b_asic.operation import *
 from b_asic.precedence_chart import *
 from b_asic.port import *
@@ -12,3 +14,4 @@ from b_asic.schema import *
 from b_asic.signal_flow_graph import *
 from b_asic.signal import *
 from b_asic.simulation import *
+from b_asic.traverse_tree import *