Better fix for Import via ${}. deep import plugins

lib/mission-file.js

@@ -1036,6 +1036,8 @@ class MissionFile {
         }
         if (!name) {
             this.error({ message: `Import without a name` })
+        } else {
+            name = await interpolate(name, this.data)
         }
         if (path.extname(name) === ".js") {
             await this.fromScript(name)
@@ -1065,6 +1067,9 @@ class MissionFile {
             /////////////////////////////////////////////
             // 
             this.removePluginsFromImport(mission)
+            if (mission.plugins) {
+                Object.assign(this.plugins, mission.plugins)
+            }
             Object.assign(this.data, mission.data)
             Object.assign(this.templates, mission.templates)
             //main.addErrors(mission)
@@ -1082,6 +1087,7 @@ class MissionFile {
      * @param {MissionFile} mission The Imported Data
      */
     removePluginsFromImport(mission) {
+        delete mission.data._
         delete mission.data.utils
         delete mission.data.int
         delete mission.data.float

test/fragments/xml/expected/import-script-simple-fragment.xml

@@ -1,8 +1,8 @@
 <mission_data version="1.0">
   <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>
   <start>
-    <big-message/>
-    <big-message title="Hello, Javascript"/>
+    <big-message title="template Hello, Javascript"/>
+    <big-message title="template Hello, Javascript"/>
     <big-message title="inline Hello, Javascript"/>
     <big-message title="Instance Hello, Plugin"/>
     <big-message title="Property Hello, property"/>

test/fragments/xml/expected/import-value-import-fragment.xml

@@ -0,0 +1,6 @@
+<mission_data version="1.0">
+  <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>
+  <start>
+    <big_message title="Indirect" subtitle1="Import"/>
+  </start>
+</mission_data>

test/fragments/xml/expected/script-simple-fragment.xml

@@ -1,7 +1,7 @@
 <mission_data version="1.0">
   <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>
   <start>
-    <big-message title="Hello, Javascript"/>
+    <big-message title="template Hello, Javascript"/>
     <big-message title="inline Hello, Javascript"/>
     <big-message title="Instance Hello, Plugin"/>
     <big-message title="Property Hello, property"/>

test/fragments/xml/import-value-import-fragment.xml

@@ -0,0 +1,7 @@
+<mission_data version="1.0">
+    <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>
+    <imports>
+        <import name="import-value-import-value.xml" />
+        <import name="import-value-import-${indirect}.xml" />
+    </imports>
+</mission_data> 

test/fragments/xml/import-value-import-import.xml

@@ -0,0 +1,7 @@
+<mission_data version="1.0">
+    <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>
+    <start>
+         <big_message title="Indirect" subtitle1="Import"/>
+
+    </start>
+</mission_data> 

test/fragments/xml/import-value-import-value.xml

@@ -0,0 +1,5 @@
+<mission_data version="1.0">
+  <values>
+    <value indirect="import"/>
+  </values>
+</mission_data>

test/fragments/xml/script-simple-fragment.xml

@@ -1,7 +1,7 @@
 <mission_data version="1.0">
     <templates>
         <template name="test">
-            <big-message title="${plugins.MyPlugin.message}"/>
+            <big-message title="template ${plugins.MyPlugin.message}"/>
         </template>
     </templates>
     <mission_description>  Multiplayer mission with Jump drive ships. Capture the most eggs by towing them to your station. Eggs can only be towed at impulse. Comms Button at start of mission must be pressed to join game. </mission_description>