Asammdf

Fixes
* fix for csv export with time_as_date and single_time_base
* fix export
* fix channel list view


Changes
* use canmatrix 0.8
* improve performance of mdf v4 TABX and RTABX conversion
* removed _excel_ export
* skip channel groups without channels when the export is called with single_time_base=False

Fixes
* fix stand alone builds in appveyor (use canmatrix development branch)

Fixes
* fix working with latest canmatrix code
* fix mdf v4 TABX conversion

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_

Fixes
* fixes issue 179
* fix _debug_channel_ utility function
* fix _get_master_ for vlsd channel group


Changes
* add horizontal and vertical tiling for sub-plots
* bring back individual axis
* improve CSV export for CAN logging
* added _raw_ argument to _get_group_ and _to_dataframe_ methods
* add possibility to ignore invalid signals (all bits are padded with 1) when extracting CAN bus logging
* link sub-plot cursors (issue 182)
* improve performance of initial plot display

Stand-alone GUI builds
* [Linux](https://ci.appveyor.com/project/danielhrisca/asammdf/builds/24413313/job/5hp42gdqtv77tpgs/artifacts)
* [Windows](https://ci.appveyor.com/project/danielhrisca/asammdf/builds/24413313/job/7sadqvyb62kt8cnj/artifacts)

Fixes
* fixes issues 174, 176
* fix export of empty channel groups

Changes
* add batch processing mode to GUI (issue 171)
* handle CAN signal multiplexing (issue 175)
* don't show empty parenthesis in the axis label if the signal has no unit

Stand-alone GUI builds
* [Linux](https://ci.appveyor.com/project/danielhrisca/asammdf/builds/24279211/job/hswd3w0945i01ob4/artifacts)
* [Windows](https://ci.appveyor.com/project/danielhrisca/asammdf/builds/24279211/job/roi9y0p9alore72p/artifacts)