Very initial implementation of smart completion

idea/testData/completion/smart/WithQualifier.kt

@@ -0,0 +1,23 @@
+trait Foo{
+    fun foo1() : String
+    fun foo2() : Object
+    val prop : String
+}
+
+val foo = Foo()
+
+fun f(p1: Foo, p2: String) {
+    var a : String
+    a = p1.<caret>
+}
+
+fun Foo.ext() : String{}
+
+// EXIST: foo1
+// ABSENT: foo2
+// EXIST: prop
+// EXIST: ext
+// ABSENT: foo
+// ABSENT: p1
+// ABSENT: p2
+// ABSENT: a