Use logging.progress if available.

Only for a few very high level things. If not available, route it to
logging.info

csppfetch/__init__.py

@@ -37,6 +37,15 @@ if sys.version_info < MIN_PYTHON_TUPLE:
 
 
 
+def logprogress(msg):
+    """ Pass to logging.progress if available, otherwise logging.info """
+    try:
+        logging.progress(msg)
+        return
+    except:
+        pass
+    logging.info(msg)
+
 
 
 
@@ -778,15 +787,17 @@ class Downloader:
 
         for attempt in range(1, retries+1):
             if retries > 1:
-                logging.info(f"Attempt {attempt}")
+                logprogress(f"Attempt {attempt}")
             for fileset in filesets:
                 description = fileset.description
                 expected = fileset.expected
                 urls_to_files = fileset.urls_to_files
-                logging.info(f"Working on {description}")
+                logprogress(f"  Working on {description}")
+                logging.info(f"    files to get: {urls_to_files}")
 
                 for base_url in base_urls:
                     full_urls_to_file = {base_url+suffix: dst+"/"+value for suffix,value in urls_to_files.items()}
+                    logging.info(f"    Trying {base_url}")
 
                     try:
                         logging.debug(f"Considering {full_urls_to_file}")