Merge branch 'feature/list-where' of git://github.com/zeckalpha/wren into zeckalpha-feature/list-where

Conflicts:
	builtin/core.wren
	src/wren_core.c

test/list/where.wren

@@ -0,0 +1,8 @@
+var a = [1, 2, 3]
+var moreThan1 = fn (x) { return x > 1 }
+var moreThan10 = fn (x) { return x > 10 }
+var b = a.where(moreThan1)
+var c = a.where(moreThan10)
+
+IO.print(b) // expect: [2, 3]
+IO.print(c) // expect: []