Refactor Value and EvaluatorOutput models in order to get rid of optionals(?)

modules/lang/src/main/kotlin/io/smnp/ext/lang/method/CharAtMethod.kt

@@ -12,7 +12,7 @@ import io.smnp.type.model.Value
 class CharAtMethod : Method(ofType(STRING),"charAt") {
    override fun define(new: MethodDefinitionTool) {
       new method simple(ofType(INT)) body { _, obj, (index) ->
-         Value.string((obj.value!! as String).getOrNull(index.value!! as Int)?.toString() ?: throw EvaluationException("Index '${index.value!!}' runs out of string bounds"))
+         Value.string((obj.value as String).getOrNull(index.value as Int)?.toString() ?: throw EvaluationException("Index '${index.value}' runs out of string bounds"))
       }
    }
 }

modules/lang/src/main/kotlin/io/smnp/ext/lang/method/ListAccessMethod.kt

@@ -12,8 +12,8 @@ import io.smnp.type.model.Value
 class ListAccessMethod : Method(ofType(LIST), "get") {
     override fun define(new: MethodDefinitionTool) {
         new method simple(ofType(INT)) body { _, value, (index) ->
-            val list = value.value!! as List<Value>
-            val i = index.value!! as Int
+            val list = value.value as List<Value>
+            val i = index.value as Int
 
             if(i >= list.size) {
                 throw EvaluationException("Index '$i' runs out of array bounds")

modules/lang/src/main/kotlin/io/smnp/ext/lang/method/MapAccessMethod.kt

@@ -12,8 +12,8 @@ import io.smnp.type.model.Value
 class MapAccessMethod : Method(ofType(MAP), "get") {
     override fun define(new: MethodDefinitionTool) {
         new method simple(allTypes()) body { _, obj, (key) ->
-            val map = (obj.value!! as Map<Value, Value>)
-            map[key] ?: throw EvaluationException("Key '${key.value!!}' not found")
+            val map = (obj.value as Map<Value, Value>)
+            map[key] ?: throw EvaluationException("Key '${key.value}' not found")
         }
     }
 }