Use flake8 if available instead of pyflakes

With flake8, we can check for more issues and ignore those who are not
real issues.

This allowed me to find genuine errors in:
- modules/boursorama/pages/account_history.py
- modules/ing/pages/login.py
- weboob/tools/application/qt/qt.py
I left one in weboob/tools/browser/browser.py for the time being.

Some PEP8 fixes on other files.

weboob/applications/masstransit/masstransit.py

@@ -24,6 +24,7 @@ from logging import warning
 
 import gtk
 
+
 class FakeConic(object):
     STATUS_CONNECTED = None
     STATUS_DISCONNECTED = None
@@ -37,11 +38,11 @@ except ImportError:
 else:
     toolkit = hildon
 
-try :
+try:
     import conic
 except ImportError:
     warning("conic is not found")
-    conic = FakeConic()
+    conic = FakeConic()  # NOQA
 
 
 from logging import debug
@@ -70,7 +71,7 @@ class MasstransitHildon():
         self.refresh_in_progress = False
         self.connected = False
         self.weboob = weboob
-        try :
+        try:
             self.connection = conic.Connection()
             self.connection.connect("connection-event", self.connect_event)
             self.connection.set_property("automatic-connection-events", True)
@@ -80,7 +81,7 @@ class MasstransitHildon():
 
         horizontal_box = gtk.HBox()
         self.main_window = toolkit.Window()
-        try :
+        try:
             self.refresh_button = toolkit.Button(
                 gtk.HILDON_SIZE_AUTO_WIDTH | gtk.HILDON_SIZE_FINGER_HEIGHT,
                 hildon.BUTTON_ARRANGEMENT_HORIZONTAL,
@@ -223,7 +224,7 @@ class MasstransitHildon():
         "the refresh button is clicked"
         debug("on_refresh_button_clicked")
         self.refresh_in_progress = True
-        try :
+        try:
             self.connection.request_connection(conic.CONNECT_FLAG_NONE)
         except AttributeError:
             if isinstance(conic, FakeConic):
@@ -232,7 +233,7 @@ class MasstransitHildon():
                 raise
 
     def check_station_input(self, widget, user_data):
-        if self.combo_source.get_current_text() is None :
+        if self.combo_source.get_current_text() is None:
             self.picker_button_dest.set_sensitive(False)
             self.refresh_button.set_sensitive(False)
             self.retour_button.set_sensitive(False)
@@ -251,7 +252,7 @@ class MasstransitHildon():
         banner.set_timeout(10000)
         hildon.hildon_gtk_window_set_progress_indicator(self.main_window, 1)
         self.treestore.clear()
-        try :
+        try:
             source_text = self.combo_source.get_current_text()
             dest_text = self.combo_dest.get_current_text()
         except AttributeError: