update readme

README.md

@@ -39,13 +39,14 @@ Use the Command Line Interface to handle the Combine tool. Positional arguments
 
 ```
 positional arguments:
-  destination    path to destination *.tif file
-  sources        path to destination source files
-
-options:
-  -h, --help     show this help message and exit
-  --test         test run with 20 windows
-  --mrt_template write template for MRT 
+  destination    path to destination *.tif and *.csv files
+  sources        path to source file(s)
+
+optional arguments:
+  -h, --help       show this help message and exit
+  --test           test run with 20 windows
+  --mrt_template   Write MRT template to file
+  --w_size         Window size in pixels (1-sided). Default=2000
 ```
 
 For example, the following input takes 2 input rasters: