Fix watched_at date for history entries + support TV shows + foreign characters

[awendland]

Howdy @yulrizka. Thank you very much for creating this script! It made migrating to Trakt.tv so much easier than I had anticipated.

I made a few modifications to the script when I did my import a few days ago, and I wanted to offer them back to upstream to help other people who will be doing similar imports in the future. I intended to keep all changes within the original intent of your script, so hopefully they will be easy to accept. Please let me know if there is anything you'd like redacted to better fit your original intent. The changes I made are:

• Adding support for UTF-8 characters in the IMDB ratings CSV file. I was having issues with a director's name that had an accent in it, but by adopting a different Ruby CSV import approach that works with the File module it appears to handle UTF-8 correctly (my languages of familiarity are not Ruby, so apologies if this is not actually a preferred approach. I found it at https://stackoverflow.com/a/38029962).
• Adding a watched_at property to requests made to the sync/history endpoint. Without this property all the items are logged as being watched today, which I assume is not the intent. This watched_at property is set to the same date and time as the rated_at property used for the sync/ratings endpoint.
• Added support for TV Show Episodes for both sync/ratings and sync/history. I had several in my imdb-ratings.csv and was therefore able to test this functionality.
• Removed recording TV Shows from being submitted to sync/history. Because this would log all episodes as being watched on the same day, which I assume is rarely if ever the case in reality, I thought it might be best to only rate the TV Shows and avoid recording a watch history event with them. I left a comment in the source code that could be uncommented if someone wants this feature.

Thanks again for creating this script! It was a huge time saver for me and got me excitedly using Trakt.tv!

[awendland]

I forgot to mention that this also incorporates the changes discussed in #6, #5, and #4 to handle the new "Date Rated" header (replacing the old "Date Added" header name).

[yulrizka]

Hi Thanks for the fixes. Looks good. I just has some minor comments to make the README more concise.

[yulrizka]

Thanks @awendland for the contribution and keeping the project up. Also complements for the thorough description :)