ref: Rewrite depcop to check transitive dependencies.

This is rewrite of most depcop functionality.  I started out
simply wanting to change the implementation to check transitive
dependencies, but the original implementation was complicated and
hard to inject this feature.  So I've restructured things and
added more tests.

On the user side, I've removed "incoming" dependency checking,
since it doesn't provide enough benefits to outweigh the extra
complexity and configuration.  I've also simplified the format of
the GO.PACKAGES file as a result.

I've also updated all GO.PACKAGE files to follow the new
formatting, and to remove some unnecessary allowed dependencies.
After this is submitted we can go through and more methodically
restrict dependencies throughout v.io.

Closes vanadium/issues#394

MultiPart: 4/4

Change-Id: I18fbb088a3eaa87e23d8eb4a2748f8e459ab91ea
diff --git a/cmd/GO.PACKAGE b/cmd/GO.PACKAGE
deleted file mode 100644
index 5100003..0000000
--- a/cmd/GO.PACKAGE
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-	"dependencies": {
-		"incoming": [
-			{"allow": "v.io/x/ref/cmd/..."},
-			{"deny": "..."}
-		]
-	}
-}
diff --git a/services/GO.PACKAGE b/services/GO.PACKAGE
deleted file mode 100644
index d1f6537..0000000
--- a/services/GO.PACKAGE
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-	"dependencies": {
-		"incoming": [
-			{"allow": "v.io/x/browser/runner/...", "comment":"temporarily allowing dependency from v.io/x/runner"},
-			{"allow": "v.io/x/ref/services/..."},
-			{"allow": "v.io/x/ref/test/modules", "comment":"temporarily allowing dependency from lib"},
-			{"allow": "v.io/x/ref/test/v23tests", "comment":"temporarily allowing dependency from lib"},
-			{"allow": "v.io/x/ref/lib/...", "comment":"temporarily allowing dependency from lib"},
-			{"allow": "v.io/x/ref/profiles/...", "comment":"temporarily allowing dependency from profiles"},
-			{"allow": "v.io/x/ref/cmd/...", "comment":"temporarily allowing dependency from v.io/x/ref/cmd"},
-			{"deny": "..."}
-		]
-	}
-}
diff --git a/services/mounttable/GO.PACKAGE b/services/mounttable/GO.PACKAGE
deleted file mode 100644
index 90b6419..0000000
--- a/services/mounttable/GO.PACKAGE
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-	"dependencies": {
-		"incoming": [
-			{"allow": "...", "comment":"We allow access to the mounttable as a library"}
-		]
-	}
-}