This release fixes the following tickets:
* #62: Instead of or in addition to the Restore Default Zoom button, add
Full Zoom Out button.
* #64: Load multiple trace files and enable the possibility to view
signals from different files in a single window.
* partial #66: key shortcuts for actions like zoom in/out, go to
next/prev event etc
* #70: add full zoom and zoom between markers (once we had markers)
* #75: marker is often hiding events underneath for highlighting and
getting transaction details
* #82: Implement help for keyboard shortcuts
