make: introduce *_default pseudo-modules

Fixes #2971

Makefile.dep

@@ -56,6 +56,12 @@ ifneq (,$(filter ng_nomac,$(USEMODULE)))
   USEMODULE += ng_netbase
 endif
 
+ifneq (,$(filter ng_sixlowpan_default,$(USEMODULE)))
+  USEMODULE += ng_ipv6_default
+  USEMODULE += ng_sixlowpan
+  USEMODULE += ng_sixlowpan_frag
+endif
+
 ifneq (,$(filter ng_sixlowpan_frag,$(USEMODULE)))
   USEMODULE += ng_sixlowpan
   USEMODULE += vtimer
@@ -72,6 +78,18 @@ ifneq (,$(filter ng_sixlowpan_ctx,$(USEMODULE)))
   USEMODULE += vtimer
 endif
 
+ifneq (,$(filter ng_ipv6_default,$(USEMODULE)))
+  USEMODULE += ng_ipv6
+  USEMODULE += ng_icmpv6
+  USEMODULE += ng_ndp
+endif
+
+ifneq (,$(filter ng_ipv6_router_default,$(USEMODULE)))
+  USEMODULE += ng_ipv6_router
+  USEMODULE += ng_icmpv6
+  USEMODULE += ng_ndp
+endif
+
 ifneq (,$(filter ng_ndp,$(USEMODULE)))
   USEMODULE += ng_icmpv6
   USEMODULE += random
@@ -85,6 +103,7 @@ ifneq (,$(filter ng_icmpv6_echo,$(USEMODULE)))
 endif
 
 ifneq (,$(filter ng_icmpv6,$(USEMODULE)))
+  USEMODULE += ng_inet_csum
   USEMODULE += ng_ipv6
 endif
 
@@ -98,17 +117,12 @@ ifneq (,$(filter ng_ipv6_router,$(USEMODULE)))
 endif
 
 ifneq (,$(filter ng_ipv6,$(USEMODULE)))
-  USEMODULE += ng_icmpv6
   USEMODULE += ng_inet_csum
   USEMODULE += ng_ipv6_addr
   USEMODULE += ng_ipv6_hdr
   USEMODULE += ng_ipv6_nc
   USEMODULE += ng_ipv6_netif
-  USEMODULE += ng_ndp
   USEMODULE += ng_netbase
-  USEMODULE += random
-  USEMODULE += timex
-  USEMODULE += vtimer
 endif
 
 ifneq (,$(filter ng_ipv6_nc,$(USEMODULE)))

Makefile.pseudomodules

 PSEUDOMODULES += defaulttransceiver
 PSEUDOMODULES += transport_layer
+PSEUDOMODULES += ng_ipv6_default
 PSEUDOMODULES += ng_ipv6_router
+PSEUDOMODULES += ng_ipv6_router_default
 PSEUDOMODULES += pktqueue
 PSEUDOMODULES += ng_netbase
+PSEUDOMODULES += ng_sixlowpan_default
 
 # include variants of the AT86RF2xx drivers as pseudo modules
 PSEUDOMODULES += ng_at86rf23%