Add whipper useragent to AccurateRip requests

Don't think it's required but it would be impolite not to announce
the software making the requests with its name, version and
contact information.

Fixes #439.

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/common/accurip.py

@@ -21,6 +21,7 @@
 
 import requests
 import struct
+import whipper
 from os import makedirs
 from os.path import dirname, exists, join
 
@@ -127,9 +128,10 @@ def calculate_checksums(track_paths):
 
 def _download_entry(path):
     url = ACCURATERIP_URL + path
+    UA = "whipper/%s ( https://github.com/whipper-team/whipper )" % whipper.__version__  # noqa: E501
     logger.debug('downloading AccurateRip entry from %s', url)
     try:
-        resp = requests.get(url)
+        resp = requests.get(url, headers={'User-Agent': UA})
     except requests.exceptions.ConnectionError as e:
         logger.error('error retrieving AccurateRip entry: %r', e)
         return None