Boxplots fail if a category has zero entries

[David Platten]

This can happen if a user chooses to plot a bar chart and box plot. The existing box plot code removes na entries from the df_value_col. This can then leave unused x_ray_system_name categories, which causes the plot to completely fail.

The fix is to remove unused x_ray_system_categories after the dropna in the plotly_boxplot method.

[David Platten]

Removing unused x_ray_system_name categories after the dropna command in the boxplot routine. This prevents failure of boxplots if there are any x_ray_system_name categories with no data. Also removed unnecessary FutureWarning suppression in two places as these commands no longer result in the warning. Also added a description of the char_wrap parameter in create_dataframe method. Refs issue #992

→ <<cset a61d4121b700>>

[David Platten]

Fixing merge conflict with changes file [skip ci]. Refs issue #992

→ <<cset ba33492326db>>

[David Platten]

Merged in issue992BoxPlotFailureIfEmptyXraySystemCategories (pull request #586)

Removing unused x_ray_system_name categories after the dropna command in the boxplot routine to prevent failure of boxplots

Approved-by: Ed McDonagh

Fixes issue #992

→ <<cset 0d2ec0806546>>