Bunch of usability improvements, some bug fixes and functional enhancements

[jikamens]

Thanks for these scripts! I found them quite useful and I was glad not to have to write them from scratch myself!

I'm submitting some changes which I believe are improvements. I've tried to isolate them logically in separate commits.

The only change I'm unsure about is 583f17c. Your code uses the "storeId" field, if it is returned by the API, rather than the "id" field. I found that none of the songs for which the API returned a "storeId" were actually being added to my playlists. When I modified the code to always use "id", all of those songs were imported properly into my playlists.

Since I don't understand the API or your usage of it well enough to understand why "storeId" was being used in your code, I don't know what the global ramifications of my change are. All I know is that, for me at least, the import worked properly without "storeId", and improperly with it.

I've mentioned this change first because as I said it's the one change I can't say for certain is correct. Here are the other changes, which I'm much more confident about:

• Use argparse for parsing the command line in both ImportList.py and ExportLists.py.
• Add support for an INI file.
• Make the username be specified on the command line or in the INI file rather than hard-coding it in preferences.py.
• Make it possible to specify the android ID on the command line or in the INI file or have the script automatically generate and save a random android ID into the INI file for future use (necessary because the script wouldn't work for me when I used MobileClient.FROM_MAC_ADDRESS, and I assume others will have the same problem).
• Add the ability to automatically replace existing playlists with the same name when importing one, so the user doesn't end up with many playlists with the same name.
• Allow the password to be specified in the INI file. Not recommended for long-term use, I know, but it's awful useful in the short term when you need to run the script over and over to import a lot of playlists and/or debug issues with the script.
• Be smarter about picking the best match for a track and about dropping duplicates. In particular:
  • When there's more than one match, and some of the matches have already been selected and others haven't, then select one of the matches that hasn't been selected yet, rather than selecting the first match.
  • When there's more than one match, prefer exact matches for title, album, or artist, over substring matches.

[nicman23]

if a song is not found then i get:

Traceback (most recent call last):
  File "ImportList.py", line 301, in <module>
    search_result = search_for_track(smart_details)
  File "ImportList.py", line 125, in search_for_track
    top_result = best_match(details, search_results)
  File "ImportList.py", line 86, in best_match
    return pairs[0][0]

[jikamens]

Fixed in 17d8ede, I hope.