allow user to access "Highlight" and "Settings" features from the .show() method

[Gdsimms]

The first thing I do with every dtale window I create is go to the "Settings" menu and turn on "Vertical Column Headers." This does not seem to be accessible from the .show() command itself. It would be nice to have some more programmatic flexibility in calling the .show() method to turn on commonly used or situationally desired features.

[aschonfeld]

So I am able to turn on "Vertical Column Headers" by doing the following:

import dtale
import pandas as pd

dtale.show(pd.DataFrame([dict(x=1, y=2, z=3)]), vertical_headers=True)

And you should be able to choose from the different highlight modes by doing the following:

import dtale
import pandas as pd

dtale.show(pd.DataFrame([dict(x=1, y=2, z=3)]), background_mode="dtypes")

The different background mode options are:

• heatmap-all: turn on heatmap for all numeric columns where the colors are determined by
  the range of values over all numeric columns combined
• heatmap-col: turn on heatmap for all numeric columns where the colors are determined by
  the range of values in the column
• heatmap-col-[column name]: turn on heatmap highlighting for a specific column
• dtypes: highlight columns based on it's data type
• missing: highlight any missing values (np.nan, empty strings, strings of all spaces)
• outliers: highlight any outliers
• range: highlight values for any matchers entered in the "range_highlights" option
• lowVariance: highlight values with a low variance