Cleanup according to the review

Author: radumcostache

Source/Core/AST/Implementation.cs

@@ -660,7 +660,6 @@ public override void Typecheck(TypecheckingContext tc)
           if (!graph.Reducible)
           {
             this.ConvertToReducible(null);
-            tc.Impl = this;
             graph = Program.GraphFromImpl(this);           
           }
 

Source/ExecutionEngine/CommandLineOptions.cs

@@ -1812,7 +1812,7 @@ skip any implementation with resolution or type checking errors
                 default is -1, which means loops are not unrolled
   /extractLoops
                 convert all irreducible loops to reducible forms by node splitting
-                and extract reducible loops into recursive procedures and
+                and extract all loops into recursive procedures
   /soundLoopUnrolling
                 sound loop unrolling
   /kInductionDepth:<k>

Source/VCGeneration/Transformations/RemoveBackEdges.cs

@@ -83,13 +83,9 @@ private void ConvertCfg2DagStandard(Implementation impl, Dictionary<Block, List<
 
     #region Create the graph by adding the source node and each edge
 
-    // Graph<Block> g = Program.GraphFromImpl(impl);
     Graph<Block> g = impl.ConvertToReducible(generator.Options);
 
     #endregion
-
-    //Graph<Block> g = program.ProcessLoops(impl);
-
     #endregion
 
     #region Cut the backedges, push assert/assume statements from loop header into predecessors, change them all into assume statements at top of loop, introduce havoc statements