remove ravenui.py by using plugin registry instead

bigtext.py

@@ -21,7 +21,6 @@ from line import Line
 from logFileModel import LogFileModel
 from raven.pluginregistry import PluginRegistry
 
-from ravenui import RavenUI
 from settings import Settings
 from watchdog.observers import Observer
 from watchdog.events import FileSystemEventHandler
@@ -159,7 +158,7 @@ class InnerBigText(QWidget):
             old_font_size = self.model.settings.getint_session('general', 'font_size')
             new_font_size = max(4, min(50, old_font_size - direction))
             self.model.settings.set_session('general', 'font_size', str(new_font_size))
-            RavenUI.update_ui()
+            PluginRegistry.execute("update_ui")
             self.update()
         else:
             # print("wheel event fired :) %s" % (direction))