Added a warning for Qt4 when missing deps

Added a warning when started with the Qt4 front-end and the ui_*.py files
are missing. These are generated by generateFiles.sh, as specified in the
README

Signed-off-by: Stéphane Bisinger <stephane.bisinger@gmail.com>

amsn2/gui/front_ends/qt4/chat_window.py

@@ -23,7 +23,12 @@
 from PyQt4.QtCore import *
 from PyQt4.QtGui import *
 from PyQt4 import *
-from ui_chatWindow import Ui_ChatWindow
+try:
+    from ui_chatWindow import Ui_ChatWindow
+except ImportError, e:
+    # FIXME: Should do that with logging...
+    print "WARNING: To use the QT4 you need to run the generateFiles.sh, check the README"
+    raise e
 from amsn2.core.views import ContactView, StringView
 
 class InputWidget(QTextEdit):

amsn2/gui/front_ends/qt4/contact_list.py

@@ -24,7 +24,12 @@
 from PyQt4.QtGui import *
 from contact_model import ContactModel
 from contact_item import ContactItem
-from ui_contactlist import Ui_ContactList
+try:
+    from ui_contactlist import Ui_ContactList
+except ImportError, e:
+    # FIXME: Should do that with logging...
+    print "WARNING: To use the QT4 you need to run the generateFiles.sh, check the README"
+    raise e
 from styledwidget import StyledWidget
 from amsn2.core.views import StringView, ContactView
 from amsn2.gui import base

amsn2/gui/front_ends/qt4/login.py

@@ -2,7 +2,12 @@
 
 from PyQt4.QtCore import *
 from PyQt4.QtGui import *
-from ui_login import Ui_Login
+try:
+    from ui_login import Ui_Login
+except ImportError, e:
+    # FIXME: Should do that with logging...
+    print " WARNING: To use the QT4 you need to run the generateFiles.sh, check the README"
+    raise e
 from styledwidget import StyledWidget