Fixes
* handle common axis label color depending of the plot background
* fix highlight issue in dark theme
* fix signal stack and fit in the plots
* fix flickering in GUI in case of mat export
* increase float constant precision when adding computed channels
Changes
* improve initial plot display speed
* use a single button for plot, numeric and tabular window creation
* add _plot_ function
* add tabular window (issue 183)
* add file information tab
* remove missing CAN metadata warning
* remove _dataframe_ argument from the _select_ method
* add copy method to Signal
* apply sub-plot link to numeric windows
* add _ignore_value2text_conversions_ argument to _select_ and _to_dataframe_