tests: Simplify the no color logging setting
loggable: Make sure funcname is always set
loggable: Pass the correct file path when calling handler
loggable: Reuse the code calling the handlers
loggable: Fix the getFileLine return value when there is an error
tests: Resurrect test_log
tests: Update the ProjectManager unittests

Also moved them to test_project.py so they can be found easily since the
ProjectManager class is in project.py.
tests: Move the system module tests to test_system

Also some cleanup in the file headers.
loggable: Remove twisted-related logic
tests: Skip TestGnomeSystem.testPowerInhibition if the power is inhibited
mainwindow: Move the preview asset logic to a new class
mainwindow: Allow pressing ESC or q to close the preview asset window
elements: Make sure the line remains straight when adding a keyframe when clicked

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=711168
elements: Fix lines appearing a bit to the left

This broke recently in 54408036318a624b4ccade928dcc4fdbe93b74b9
elements: Get the main window from the container
mediafilespreviewer: Clarify what parameter the PreviewWidget constructor expects
medialibrary: Move function in the class where it's used
medialibrary: Make sure the comparator for the media library model is strict
ui: Clarify what beautify_info receives
ui: Clarify what parameters info_name accepts