image re-project now uses offscreen render function and has input for render size.

unrelated changes that ended up being more trouble to commit separate...

- removed BLI_split_dirfile(), was nasty, occasionaly modifying the source string, it could create directories and used the $CWD in some cases. was only used in 2 places in filesel.c, if this gives problems can address without bringing back this function.
  renamed BLI_split_dirfile_basic --> BLI_split_dirfile

- view3d_operator_needs_opengl was being called for offscreen render when it wasnt needed.

source/gameengine/Ketsji/KX_PythonInit.cpp

@@ -474,7 +474,7 @@ static PyObject* gPyGetBlendFileList(PyObject*, PyObject* args)
 		BLI_convertstringcode(cpath, gp_GamePythonPath);
 	} else {
 		/* Get the dir only */
-		BLI_split_dirfile_basic(gp_GamePythonPath, cpath, NULL);
+		BLI_split_dirfile(gp_GamePythonPath, cpath, NULL);
 	}
 	
     if((dp  = opendir(cpath)) == NULL) {
@@ -1786,7 +1786,7 @@ static void initPySysObjects__append(PyObject *sys_path, char *filename)
 	PyObject *item;
 	char expanded[FILE_MAXDIR + FILE_MAXFILE];
 	
-	BLI_split_dirfile_basic(filename, expanded, NULL); /* get the dir part of filename only */
+	BLI_split_dirfile(filename, expanded, NULL); /* get the dir part of filename only */
 	BLI_convertstringcode(expanded, gp_GamePythonPath); /* filename from lib->filename is (always?) absolute, so this may not be needed but it wont hurt */
 	BLI_cleanup_file(gp_GamePythonPath, expanded); /* Dont use BLI_cleanup_dir because it adds a slash - BREAKS WIN32 ONLY */
 	item= PyUnicode_FromString(expanded);