Refactor/de-duplicate entity text input

This is basically FIQ's patch from VCE, except he never upstreamed it
because he said something along the lines of it seeming to not fit the
purpose of upstream.

But anyway, it basically just de-duplicates all the text input and text
finishing handling code and cuts down on the large amount of copy-paste
in the editor functions. It makes things way more maintainable.

Interesting note, it seems like FIQ had the intent to refactor the text
input in editor settings (i.e. the level metadata details), but never
got around to it in VCE. Maybe we'll finish that job for him later.

desktop_version/src/editor.h

@@ -8,6 +8,30 @@
 #include "Script.h"
 #include "Graphics.h"
 
+// Text entry field type
+enum textmode {
+  TEXT_NONE,
+
+  // In-editor text fields
+  TEXT_LOAD,
+  TEXT_SAVE,
+  TEXT_ROOMNAME,
+  TEXT_SCRIPT,
+  TEXT_ROOMTEXT,
+  LAST_EDTEXT = TEXT_ROOMTEXT,
+
+  // Settings-mode text fields
+  TEXT_TITLE,
+  TEXT_DESC,
+  TEXT_WEBSITE,
+  TEXT_CREATOR,
+  NUM_TEXTMODES,
+
+  // Text modes with an entity
+  FIRST_ENTTEXT = TEXT_SCRIPT,
+  LAST_ENTTEXT = TEXT_ROOMTEXT
+};
+
 class edentities{
 public:
   int x, y, t;
@@ -105,6 +129,7 @@ class editorclass{
 
   void saveconvertor();
   void reset();
+  void getlin(const enum textmode mode, const std::string& prompt, std::string* ptr);
   std::vector<int> loadlevel(int rxi, int ryi);
 
   void placetile(int x, int y, int t);
@@ -184,14 +209,17 @@ class editorclass{
   int levx, levy;
   int entframe, entframedelay;
 
-  bool roomtextmod;
-
-  bool scripttextmod;
-  int textent;
   int scripttexttype;
   std::string oldenttext;
 
-  bool xmod, zmod, cmod, vmod, bmod, hmod, spacemod, warpmod, roomnamemod, textentry, savemod, loadmod;
+  enum textmode textmod; // In text entry
+  std::string* textptr; // Pointer to text we're changing
+  std::string textdesc; // Description (for editor mode text fields)
+  union {
+    int desc; // Which description row we're changing
+    int textent; // Entity ID for text prompt
+  };
+  bool xmod, zmod, cmod, vmod, bmod, hmod, spacemod, warpmod, textentry;
   bool titlemod, creatormod, desc1mod, desc2mod, desc3mod, websitemod;
 
   int roomnamehide;