Android Extensions: Add missing documentation, move the hasCache property to the compiler module

plugins/android-extensions/android-extensions-runtime/src/kotlinx/android/extensions/CacheImplementation.kt

@@ -16,15 +16,20 @@
 
 package kotlinx.android.extensions
 
+/**
+ * Caching mechanism for [LayoutContainer] implementations, and also for the types directly supported by Android Extensions,
+ * such as [android.app.Activity] or [android.app.Fragment].
+ */
 public enum class CacheImplementation {
+    /** Use [android.util.SparseArray] as a backing store for the resolved views. */
     SPARSE_ARRAY,
+    /** Use [HashMap] as a backing store for the resolved views (default). */
     HASH_MAP,
+    /** Do not cache views for this layout. */
     NO_CACHE;
 
-    public val hasCache: Boolean
-        get() = this != NO_CACHE
-
     companion object {
+        /** The default cache implementation is [HASH_MAP]. */
         val DEFAULT = HASH_MAP
     }
 }

plugins/android-extensions/android-extensions-runtime/src/kotlinx/android/extensions/ContainerOptions.kt

@@ -18,6 +18,10 @@ package kotlinx.android.extensions
 
 import kotlinx.android.extensions.CacheImplementation.*
 
+/**
+ * Instructs Android Extensions to apply specific options for the annotated layout container.
+ */
 public annotation class ContainerOptions(
+        /** A cache implementation for the container. */
         public val cache: CacheImplementation = HASH_MAP
 )

plugins/android-extensions/android-extensions-runtime/src/kotlinx/android/extensions/LayoutContainer.kt

@@ -18,6 +18,10 @@ package kotlinx.android.extensions
 
 import android.view.View
 
+/**
+ * A base interface for all view holders supporting Android Extensions-style view access.
+ */
 public interface LayoutContainer {
+    /** Returns the root holder view. */
     public val containerView: View?
 }