Add a handler for providing evaluation context for scripts

use it on refinement.
also some refactoring on context class and around

libraries/scripting/common/src/kotlin/script/experimental/util/propertiesCollection.kt

@@ -13,7 +13,7 @@ import kotlin.reflect.KProperty
 import kotlin.reflect.KType
 import kotlin.script.experimental.api.KotlinType
 
-open class PropertiesCollection(private var properties: Map<Key<*>, Any?> = emptyMap()) : Serializable {
+open class PropertiesCollection(protected var properties: Map<Key<*>, Any?> = emptyMap()) : Serializable {
 
     open class Key<T>(
         val name: String,
@@ -64,6 +64,8 @@ open class PropertiesCollection(private var properties: Map<Key<*>, Any?> = empt
 
     val notTransientData: Map<Key<*>, Any?> get() = properties.filterKeys { it !is TransientKey<*>}
 
+    fun isEmpty(): Boolean = properties.isEmpty()
+
     override fun equals(other: Any?): Boolean =
         (other as? PropertiesCollection)?.let { it.properties == properties } == true