Upgrade to 3.5.4

What's New?
===========
Legacy chat themes from Gossip have been removed and re-implemented using the
Adium theme format.

Dependencies:
 • GLib ≥ 2.33.3
 • telepathy-glib ≥ 0.19.3

Bugs fixed:
 - Fixed #645921, Drop old chat themes and make Adium theme mandatory (Danielle Madeley)
 - Fixed #627948, Avatar option for irc superfous (Will Thompson)
 - Fixed #678331, Sending a file from the conversation window silently fails (Guillaume Desmottes)
 - Fixed #678524, [new roster] Re-Implement sending files using DnD (Guillaume Desmottes)
 - Fixed #678807, empathy-chat crashed with SIGSEGV in _tp_base_client_handle_channels() (Guillaume Desmottes)
 - Fixed #678845, Strip %senderPrefix% in Adium themes (Will Thompson)
 - Fixed #678875, empathy-nautilus-sendto should use RosterView (Laurent Contzen)
 - Fixed #679136, Stop using EmpathyContactWidget in the subscription request dialog (Guillaume Desmottes)
 - Fixed #679255, Remove EmpathyChatView (Guillaume Desmottes)
 - Fixed #679332, Handle Adium themes that use .AdiumMessagestyle (Guillaume Desmottes)
 - Fixed #679396, Bind keyboard keys on DTMF events (Guillaume Desmottes)
 - Fixed #679532, Contact names not aligned (Guillaume Desmottes)

Translations:
 - Updated be Translation (Ihar Hrachyshka)
 - Updated el Translation (Tom Tryfonidis)
 - Updated es Translation (Daniel Mustieles)
 - Updated he Translation (Yaron Shahrabani)
 - Updated lt Translation (Žygimantas Beručka)
 - Updated nb Translation (Kjartan Maraas)
 - Updated pa Translation (A S Alam)
 - Updated zh_HK Translation (Cheng-Chia Tseng)
 - Updated zh_TW Translation (Cheng-Chia Tseng)

Documentation translations:
 - Updated el Documentation translation (Tom Tryfonidis)