fix bruderstein#255 notepad.getCurrentDocIndex(v) doesn't return -1 if view 'v' is not open

use signed var for getCurrentDocIndex() return type

Author: chcg

PythonScript/src/NotepadPlusWrapper.cpp

@@ -405,7 +405,7 @@ void NotepadPlusWrapper::destroyScintilla(boost::shared_ptr<ScintillaWrapper> bu
 	}
 }
 
-idx_t NotepadPlusWrapper::getCurrentDocIndex(int view)
+intptr_t NotepadPlusWrapper::getCurrentDocIndex(int view)
 {
 	return callNotepad(NPPM_GETCURRENTDOCINDEX, 0, static_cast<LPARAM>(view));
 }

PythonScript/src/NotepadPlusWrapper.h

@@ -663,7 +663,7 @@ class NotepadPlusWrapper
 	boost::shared_ptr<ScintillaWrapper> createScintilla();
 	void destroyScintilla(boost::shared_ptr<ScintillaWrapper> buffer);
 
-	idx_t getCurrentDocIndex(int view);
+	intptr_t getCurrentDocIndex(int view);
 
 	void setStatusBar(StatusBarSection section, const char *text);