small fixes

- handle cancelled askdirectory dialog
- update README.md

Author: cornish

README.md

@@ -1,5 +1,5 @@
-anonymize-slide
-===============
+anonymize-slide-python3-gui
+===========================
 
 This adds a very simple GUI interface to [Benjamin Gilbert's anonymize-slide](https://github.com/bgilbert/anonymize-slide) program which I previously [updated to run under python3](https://github.com/cornish/anonymize-slide-python3). The CLI functions still work as previously (see below). If no CLI arguments are supplied, the GUI is launched.
 

anonymize-slide-gui.py

@@ -547,10 +547,14 @@ def gui():
 
     if not response:
         print("Cancelled")
-        sys.exit()
+        sys.exit(1)
 
     dir = fd.askdirectory(initialdir=application_path,title='Select directory')
 
+    if dir == '':
+        print("Cancelled")
+        sys.exit(1)
+
     wsi_exts = ['.svs','.ndpi','.mrxs','.py']
     filepaths = []
     for file in os.listdir(dir):