extracted constants from GRAMMAR spec
FIX: allow special EnclosingMethodTypes for annotations, yet not clear why but grammar fixed ;-)
Sample:
"
   # annotations
   .annotation system Ldalvik/annotation/EnclosingMethod;
       value = Lnet/example/MyActivity;->onCreate(Landroid/os/Bundle;)V
   .end annotation
"
FIX: allow 'null' as a value in annotations
Sample:
"
   # annotations
   .annotation system Ldalvik/annotation/EnclosingMethod;
       value = null
   .end annotation
"
FIX: allow special access modifier synthetic
Sample:
"
   .field final synthetic this$0:Lnet/example/MyActivity;
"