Very initial implementation of smart completion

idea/testData/completion/smart/ChainedCall.kt

@@ -0,0 +1,20 @@
+trait Foo{
+    public fun foo() : Foo
+    public fun s() : String
+    public val prop : String
+}
+
+val foo = Foo()
+
+fun f(p1: Foo, p2: String) {
+    var a : String
+    a = p1.foo().<caret>
+}
+
+// ABSENT: foo
+// EXIST: s
+// EXIST: prop
+// ABSENT: foo
+// ABSENT: p1
+// ABSENT: p2
+// ABSENT: a