Simple memory testing for gae/wrapper

go/src/infra/gae/libs/wrapper/memory/schema

+index row encoding
+ ints ->
+   funnybase
+ floats ->  http://stereopsis.com/radix.html
+                b := math.Float64bits(f)
+                return b ^ (-(b >> 63) | 0x8000000000000000)
+
+                return math.Float64frombits(b ^ ((b >> 63) - 1) | 0x8000000000000000)
+
+index types:
+  primary: (key -> entity)
+  kind:    (kind | key -> nil)
+  prop:    (kind | prop | val | key -> nil)
+  -prop:   (kind | prop | -val | key -> nil)
+  comp:    (kind | <[prop | ?val]+> | key -> nil)
+
+collections
+  ents:ns                    -> key -> value
+                                (rootkind, rootid, __entity_group__,1) -> {__version__: int}
+                                (rootkind, rootid, __entity_group_ids__,1) -> {__version__: int}
+                                (__entity_group_ids__,1) -> {__version__: int}
+  idx:ns:kind                -> key = nil
+  idx:ns:kind|prop           -> propval|key = [prev val]
+  idx:ns:kind|-prop          -> -propval|key = [next val]
+  idx:ns:kind|A|?prop|?prop  -> A|propval|propval|key = [prev/next val]|[prev/next val]
+  idx:ns:kind|?prop|?prop    -> propval|propval|key = [prev/next val]|[prev/next val]
+
+  // to add persistence later
+  idx:                       -> kind,A?,[-?prop]*
+
+