gui.gtkui: Implement the language combobox using a custom liststore

This allows us to also have an automatic detection option
Language: Remove the now unused LANGUAGES_DICT_R
gui.base, gui.gtkui: Properly save the used service when logging in

Closes #1135
ConversationToolbar: Block and unblock icon and tooltips
Closes #1136
Merge pull request #1138 from lfottaviano/master

Block/Unblock contact stock ids and tooltips, support for themes too.
LoginBase: fix, passes the account string
qt4ui: make it run again

if you want to try it out just run ./emesene -e main:qt4_main
Merge pull request #1141 from c10ud/master

make qt ui run again
Logger: Adds an xml writer functions, now conversation logs can be saved
to a xml file, adding .xml extension to the destination filename
Merge pull request #1142 from lfottaviano/master

logger xml
PEP8: Logger changes related to convention and style.
Merge pull request #1143 from lfottaviano/master

PEP8 suggestions for Logger.py
history exporter: adds xml exporter to category, removes unneeded call.
Merge pull request #1145 from lfottaviano/master

removes unneeded call, adds xml exporter to history exporter category
MainWindow: Only left click on e-mail is allowed.
Closes #1149
Preferences,MainWindow: Allows Hiding email icon
Closes #1150
gui.qt4ui: Properly name the present method in the Preferences window

Closes #1144
Preferences, ConvesationManager: Now escape_hotkey session.config is applied instantly
Merge branch 'master' of github.com:emesene/emesene
ConversationManager, Preferences: Close tab button hiding, is now instantly applied