Use semicolon as default CSV separator.

doc/changelog.txt

@@ -27,6 +27,8 @@ Changes:
 - logging: Prefer the <a> element content as name instead of the title
   attribute.
   Closes: SF bug #3023483
+- logging: Use semicolon as default separator for CSV files so it opens
+  in Excel initially.
 
 Features:
 - ftp: Detect and support UTF-8 filename encoding capability of FTP

linkcheck/configuration/__init__.py

@@ -121,7 +121,7 @@ class Configuration (dict):
         }
         self['csv'] = {
             "filename": "linkchecker-out.csv",
-            'separator': ',',
+            'separator': ';',
             "quotechar": '"',
         }
         self['blacklist'] = {

linkcheck/logger/csvlog.py

@@ -27,7 +27,7 @@ from .. import strformat, configuration
 class CSVLogger (Logger):
     """
     CSV output, consisting of one line per entry. Entries are
-    separated by a semicolon.
+    separated by a separator (a semicolon per default).
     """
 
     def __init__ (self, **args):