refactor filter operands

README.md

@@ -140,9 +140,15 @@ local, _ := c.Aircraft(ctx,
 
 // OR-composition and negation:
 heavies, _ := c.Aircraft(ctx,
-    readsb.Any(readsb.WithCategory("A5"), readsb.WithType("mlat")),
+    readsb.Or(readsb.WithCategory("A5"), readsb.WithType("mlat")),
     readsb.Not(readsb.OnGround()),
 )
+
+// And is the value form of the implicit AND, for nesting inside Or:
+nearby, _ := c.Aircraft(ctx, readsb.Or(
+    readsb.And(readsb.WithCategory("A7"), readsb.WithinNMOf(40.7, -74.0, 5)),
+    readsb.And(readsb.WithCategory("A7"), readsb.WithinNMOf(41.9, -72.7, 5)),
+))
 ```
 
 | Filter Name | Description | Sample Usage |
@@ -165,7 +171,8 @@ heavies, _ := c.Aircraft(ctx,
 | `SeenWithin` | Keeps aircraft heard from within the given duration. | `readsb.SeenWithin(5*time.Minute)` |
 | `MinRSSI` | Keeps aircraft whose average signal strength is at or above dbfs (e.g. -24). | `readsb.MinRSSI(-24)` |
 | `Not` | Inverts a filter. | `readsb.Not(readsb.OnGround())` |
-| `Any` | Keeps aircraft matching at least one of the supplied filters (logical OR). | `readsb.Any(f1, f2)` |
+| `And` | Keeps aircraft matching every supplied filter (logical AND). | `readsb.And(f1, f2)` |
+| `Or` | Keeps aircraft matching at least one of the supplied filters (logical OR). | `readsb.Or(f1, f2)` |
 
 ### Streaming