Fix out-of bounds read access issue for smart highlighting.

Closes #1111
See https://github.com/notepad-plus-plus/notepad-plus-plus/pull/187/files
, see also comments added in the PR:

String returned by SCI_GETWORDCHARS from scintilla is not null terminated, so check for strlen in isWordChar() below on listChar is dangerous as strlen accesses data after the buffer until the first following null is found in memory
- seen with MS Application Verifier on x64 release
- expected to also happen on win32 x86 release

PowerEditor/src/ScitillaComponent/SmartHighlighter.cpp

@@ -61,6 +61,7 @@ void SmartHighlighter::highlightView(ScintillaEditView * pHighlightView)
 	int listCharSize = pHighlightView->execute(SCI_GETWORDCHARS, 0, 0);
 	char *listChar = new char[listCharSize+1];
 	pHighlightView->execute(SCI_GETWORDCHARS, 0, (LPARAM)listChar);
+	listChar[listCharSize] = '\0';
 	
 	bool valid = true;
 	//The word has to consist if wordChars only, and the characters before and after something else