Update plugin_transmission.py

As of transmissionrpc-0.11-py2.7.egg/client.py
add() & add_uri() are deprecated.

Althought, I was getting transmissionError (Query failed with result:...) when trying to launch a new torrent. So I went in the rpc/client code and used the same syntax they use to base64 the data and everything'sback to normal working order ^^

Althought I suspect that line 339 (for id in r.keys(): ) won't work with the return from cli.add_torrent(), I'm not equipped to deal with that (don't know when it occurs)
Expand default special identifiers
Add python 2.7 check to subliminal plugin. fix #2420
Rename scenereleases plugin to sceper and update a bit.
Fix the unit test for it.
apple_trailers plugin now raises a PluginError
Disable apple_trailers test
Fix series assume_special test
Update some more plugins to new schemas
Make sure __unicode__ method of PluginError always returns unicode
Fix archive plugin schema
Let dump try converting field values to strings

Values in some fields can be objects, which may be able to produce
their own string representations. Give it a shot before outputting
'not printable'. Mostly for series_parser.
Remove broken imdb_rated plugin
Fix a bug in subtitles plugin
Make sure imdb_id field is being used over imdb_url
Cleanups
Find plugin handles filesystem encoding better.
refs #2295, #2065, #989, #1347
Make path encoding/decoding helpers a bit closer to python 3 ones
Fix --explain-sql
Add back --profile
Silence an ImportWarning from deluge plugin
Work around encoding bug in tmdb3. refs #2392